Auto merge of #21619 - brson:featureck-tidy, r=alexcrichton

Builds on my [feature staging PR](https://github.com/rust-lang/rust/pull/21248) to clean up the tidy scripts a bit, and make them much faster (6s vs ~40s).

Adds make rules 'tidy-basic', 'tidy-binaries', 'tidy-errors' and 'tidy-features'.

This is the output of `make tidy` here:

```
cfg: version 1.0.0-dev (a8c878d41 2015-01-25 01:49:14 -0800)
cfg: build triple x86_64-unknown-linux-gnu
cfg: host triples x86_64-unknown-linux-gnu
cfg: target triples x86_64-unknown-linux-gnu
cfg: host for x86_64-unknown-linux-gnu is x86_64
cfg: os for x86_64-unknown-linux-gnu is unknown-linux-gnu
cfg: good valgrind for x86_64-unknown-linux-gnu is 1
cfg: using CC=gcc (CFG_CC)
cfg: enabling valgrind run-pass tests (CFG_ENABLE_VALGRIND_RPASS)
cfg: valgrind-rpass command set to "/usr/bin/valgrind" --error-exitcode=100 --soname-synonyms=somalloc=NONE --quiet --suppressions=/home/brian/dev/rust3/src/etc/x86.supp  --tool=memcheck --leak-check=full
cfg: no lualatex found, deferring to xelatex
cfg: no xelatex found, deferring to pdflatex
cfg: no pdflatex found, disabling LaTeX docs
cfg: no pandoc found, omitting PDF and EPUB docs
cfg: including test rules
cfg: javac not available, skipping lexer test...
check: formatting

* linted .rs files: 4948
* linted .py files: 27
* linted .js files: 2
* linted .sh files: 5
* linted .pl files: 0
* linted .c files: 28
* linted .h files: 3
* other linted files: 0
* total lines of code: 481217
* total non-blank lines of code: 423682

check: binaries
check: extended errors

* 249 error codes
* highest error code: E0315

check: feature sanity

* advanced_slice_patterns         lang    unstable    None    
* alloc                           lib     unstable    None    
* asm                             lang    unstable    None    
* associated_types                lang    stable      1.0.0   
* box_syntax                      lang    unstable    None    
* collections                     lib     unstable    None    
* concat_idents                   lang    unstable    None    
* core                            lib     unstable    None    
* default_type_params             lang    stable      1.0.0   
* globs                           lang    stable      1.0.0   
* hash                            lib     unstable    None    
* if_let                          lang    stable      1.0.0   
* import_shadowing                lang    unstable    None    
* int_uint                        lang    unstable    None    
* intrinsics                      lang    unstable    None    
* io                              lib     unstable    None    
* issue_5723_bootstrap            lang    stable      1.0.0   
* lang_items                      lang    unstable    None    
* link_args                       lang    unstable    None    
* link_llvm_intrinsics            lang    unstable    None    
* linkage                         lang    unstable    None    
* log_syntax                      lang    unstable    None    
* macro_rules                     lang    stable      1.0.0   
* main                            lang    unstable    None    
* managed_boxes                   lang    unstable    None    
* non_ascii_idents                lang    unstable    None    
* old_impl_check                  lang    unstable    None    
* old_orphan_check                lang    unstable    None    
* on_unimplemented                lang    unstable    None    
* opt_out_copy                    lang    unstable    None    
* optin_builtin_traits            lang    unstable    None    
* os                              lib     unstable    None    
* path                            lib     unstable    None    
* phase                           lang    unstable    None    
* plugin                          lang    unstable    None    
* plugin_registrar                lang    unstable    None    
* quad_precision_float            lang    unstable    None    
* quote                           lang    unstable    None    
* rand                            lib     unstable    None    
* rust1                           lib     stable      1.0.0   
* rustc_diagnostic_macros         lang    unstable    None    
* rustc_private                   lib     unstable    None    
* rustdoc                         lib     unstable    None    
* simd                            lang    unstable    None    
* simd_ffi                        lang    unstable    None    
* slicing_syntax                  lang    unstable    None    
* staged_api                      lang    unstable    None    
* start                           lang    unstable    None    
* std_misc                        lib     unstable    None    
* struct_inherit                  lang    unstable    None    
* struct_variant                  lang    stable      1.0.0   
* test                            lib     unstable    None    
* test_accepted_feature           lang    stable      1.0.0   
* test_removed_feature            lang    unstable    None    
* thread_local                    lang    unstable    None    
* trace_macros                    lang    unstable    None    
* tuple_indexing                  lang    stable      1.0.0   
* unboxed_closures                lang    unstable    None    
* unicode                         lib     unstable    None    
* unsafe_destructor               lang    unstable    None    
* visible_private_types           lang    unstable    None    
* while_let                       lang    stable      1.0.0   
```

There's a lot of informational output now, which comes after things like 'NOTE's.

29 files changed, 177 insertions, 69 deletions

diff --git a/src/etc/errorck.py b/src/etc/errorck.py
index c940359abc1..7b11504f3cd 100644
--- a/src/etc/errorck.py
+++ b/src/etc/errorck.py
@@ -15,6 +15,10 @@ import sys
 import os
 import re
 
+if len(sys.argv) < 2:
+    print "usage: errorck.py <src-dir>"
+    sys.exit(1)
+
 src_dir = sys.argv[1]
 errcode_map = {}
 error_re = re.compile("(E\d\d\d\d)")
@@ -54,8 +58,10 @@ for errcode, entries in errcode_map.items():
             print("{1}: {2}\n{3}".format(*entry))
         errors = True
 
-print("{0} error codes".format(len(errcode_map)))
-print("highest error code: " + max(all_errors))
+print
+print("* {0} error codes".format(len(errcode_map)))
+print("* highest error code: " + max(all_errors))
+print
 
 if errors:
     sys.exit(1)
diff --git a/src/etc/featureck.py b/src/etc/featureck.py
index 064cf1d40ab..df4ea998fef 100644
--- a/src/etc/featureck.py
+++ b/src/etc/featureck.py
@@ -20,6 +20,10 @@
 
 import sys, os, re
 
+if len(sys.argv) < 2:
+    print "usage: featurkck.py <src-dir>"
+    sys.exit(1)
+
 src_dir = sys.argv[1]
 
 # Features that are allowed to exist in both the language and the library
@@ -235,9 +239,7 @@ for s in stats:
 lines.sort()
 
 print
-print "Rust feature summary:"
-print
 for line in lines:
-    print line
+    print "* " + line
 print
 
diff --git a/src/etc/licenseck.py b/src/etc/licenseck.py
index f38583ee1fb..889b2c95a7e 100644
--- a/src/etc/licenseck.py
+++ b/src/etc/licenseck.py
@@ -22,11 +22,6 @@ u"""(#|//) Copyright .* The Rust Project Developers. See the COPYRIGHT
 \\1 except according to those terms.""")
 
 exceptions = [
-    "rt/rust_android_dummy.cpp", # BSD, chromium
-    "rt/rust_android_dummy.h", # BSD, chromium
-    "rt/isaac/randport.cpp", # public domain
-    "rt/isaac/rand.h", # public domain
-    "rt/isaac/standard.h", # public domain
     "libstd/sync/mpsc/mpsc_queue.rs", # BSD
     "libstd/sync/mpsc/spsc_queue.rs", # BSD
     "test/bench/shootout-binarytrees.rs", # BSD
diff --git a/src/etc/tidy.py b/src/etc/tidy.py
index f5172feb5b6..fd3309dce12 100644
--- a/src/etc/tidy.py
+++ b/src/etc/tidy.py
@@ -51,78 +51,155 @@ def do_license_check(name, contents):
     if not check_license(name, contents):
         report_error_name_no(name, 1, "incorrect license")
 
-
-file_names = [s for s in sys.argv[1:] if (not s.endswith("_gen.rs"))
-                                     and (not ".#" in s)]
-
 current_name = ""
 current_contents = ""
 check_tab = True
 check_cr = True
 check_linelength = True
 
+if len(sys.argv) < 2:
+    print "usage: tidy.py <src-dir>"
+    sys.exit(1)
+
+src_dir = sys.argv[1]
 
 try:
-    for line in fileinput.input(file_names,
+    count_lines = 0
+    count_non_blank_lines = 0
+
+    interesting_files = ['.rs', '.py', '.js', '.sh', '.c', '.h']
+
+    file_counts = {ext: 0 for ext in interesting_files}
+    file_counts['other'] = 0
+
+    def update_counts(current_name):
+        global file_counts
+        _, ext = os.path.splitext(current_name)
+
+        if ext in file_counts:
+            file_counts[ext] += 1
+        else:
+            file_counts['other'] += 1
+
+    all_paths = set()
+
+    for (dirpath, dirnames, filenames) in os.walk(src_dir):
+
+        # Skip some third-party directories
+        skippable_dirs = {
+            'src/jemalloc',
+            'src/llvm',
+            'src/gyp',
+            'src/libbacktrace',
+            'src/libuv',
+            'src/compiler-rt',
+            'src/rt/hoedown',
+            'src/rustllvm',
+            'src/rt/valgrind',
+            'src/rt/msvc',
+            'src/rust-installer'
+        }
+
+        if any(d in dirpath for d in skippable_dirs):
+            continue
+
+        def interesting_file(f):
+            if "miniz.c" in f \
+            or "jquery" in f \
+            or "rust_android_dummy" in f:
+                return False
+
+            return any(os.path.splitext(f)[1] == ext for ext in interesting_files)
+
+        file_names = [os.path.join(dirpath, f) for f in filenames
+                      if interesting_file(f)
+                      and not f.endswith("_gen.rs")
+                      and not ".#" is f]
+
+        if not file_names:
+            continue
+
+        for line in fileinput.input(file_names,
                                 openhook=fileinput.hook_encoded("utf-8")):
 
-        if "tidy.py" not in fileinput.filename():
+            filename = fileinput.filename()
+
+            if "tidy.py" not in filename:
+                if "TODO" in line:
+                    report_err("TODO is deprecated; use FIXME")
+                match = re.match(r'^.*/(\*|/!?)\s*XXX', line)
+                if match:
+                    report_err("XXX is no longer necessary, use FIXME")
+                match = re.match(r'^.*//\s*(NOTE.*)$', line)
+                if match and "TRAVIS" not in os.environ:
+                    m = match.group(1)
+                    if "snap" in m.lower():
+                        report_warn(match.group(1))
+                match = re.match(r'^.*//\s*SNAP\s+(\w+)', line)
+                if match:
+                    hsh = match.group(1)
+                    date, rev = snapshot.curr_snapshot_rev()
+                    if not hsh.startswith(rev):
+                        report_err("snapshot out of date (" + date
+                            + "): " + line)
+                else:
+                    if "SNAP" in line:
+                        report_warn("unmatched SNAP line: " + line)
+
             if cr_flag in line:
                 check_cr = False
             if tab_flag in line:
                 check_tab = False
             if linelength_flag in line:
                 check_linelength = False
-            if "TODO" in line:
-                report_err("TODO is deprecated; use FIXME")
-            match = re.match(r'^.*/(\*|/!?)\s*XXX', line)
-            if match:
-                report_err("XXX is no longer necessary, use FIXME")
-            match = re.match(r'^.*//\s*(NOTE.*)$', line)
-            if match and "TRAVIS" not in os.environ:
-                m = match.group(1)
-                if "snap" in m.lower():
-                    report_warn(match.group(1))
-            match = re.match(r'^.*//\s*SNAP\s+(\w+)', line)
-            if match:
-                hsh = match.group(1)
-                date, rev = snapshot.curr_snapshot_rev()
-                if not hsh.startswith(rev):
-                    report_err("snapshot out of date (" + date
-                               + "): " + line)
-            else:
-                if "SNAP" in line:
-                    report_warn("unmatched SNAP line: " + line)
-
-        if check_tab and ('\t' in line and
-                          "Makefile" not in fileinput.filename()):
-            report_err("tab character")
-        if check_cr and not autocrlf and '\r' in line:
-            report_err("CR character")
-        if line.endswith(" \n") or line.endswith("\t\n"):
-            report_err("trailing whitespace")
-        line_len = len(line)-2 if autocrlf else len(line)-1
-
-        if check_linelength and line_len > cols:
-            report_err("line longer than %d chars" % cols)
-
-        if fileinput.isfirstline() and current_name != "":
-            do_license_check(current_name, current_contents)
-
-        if fileinput.isfirstline():
-            current_name = fileinput.filename()
-            current_contents = ""
-            check_cr = True
-            check_tab = True
-            check_linelength = True
-
-        current_contents += line
+
+            if check_tab and ('\t' in line and
+                              "Makefile" not in filename):
+                report_err("tab character")
+            if check_cr and not autocrlf and '\r' in line:
+                report_err("CR character")
+            if line.endswith(" \n") or line.endswith("\t\n"):
+                report_err("trailing whitespace")
+            line_len = len(line)-2 if autocrlf else len(line)-1
+
+            if check_linelength and line_len > cols:
+                report_err("line longer than %d chars" % cols)
+
+            if fileinput.isfirstline():
+                # This happens at the end of each file except the last.
+                if current_name != "":
+                    update_counts(current_name)
+                    assert len(current_contents) > 0
+                    do_license_check(current_name, current_contents)
+
+                current_name = filename
+                current_contents = ""
+                check_cr = True
+                check_tab = True
+                check_linelength = True
+
+            # Put a reasonable limit on the amount of header data we use for
+            # the licenseck
+            if len(current_contents) < 1000:
+                current_contents += line
+
+            count_lines += 1
+            if line.strip():
+                count_non_blank_lines += 1
 
     if current_name != "":
+        update_counts(current_name)
+        assert len(current_contents) > 0
         do_license_check(current_name, current_contents)
 
 except UnicodeDecodeError as e:
     report_err("UTF-8 decoding error " + str(e))
 
+print
+for ext in file_counts:
+    print "* linted " + str(file_counts[ext]) + " " + ext + " files"
+print "* total lines of code: " + str(count_lines)
+print "* total non-blank lines of code: " + str(count_non_blank_lines)
+print
 
 sys.exit(err)
diff --git a/src/grammar/check.sh b/src/grammar/check.sh
index cb269bbdb0a..b5be3daa13e 100755
--- a/src/grammar/check.sh
+++ b/src/grammar/check.sh
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+# ignore-license
+
 # Run the reference lexer against libsyntax and compare the tokens and spans.
 # If "// ignore-lexer-test" is present in the file, it will be ignored.
 
diff --git a/src/grammar/testparser.py b/src/grammar/testparser.py
index 38e57be288b..16babd4194e 100755
--- a/src/grammar/testparser.py
+++ b/src/grammar/testparser.py
@@ -9,6 +9,9 @@
 # <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 # option. This file may not be copied, modified, or distributed
 # except according to those terms.
+
+# ignore-tidy-linelength
+
 import sys
 
 import os
diff --git a/src/rt/rust_builtin.c b/src/rt/rust_builtin.c
index 382cbf0d5d1..6bf86f52739 100644
--- a/src/rt/rust_builtin.c
+++ b/src/rt/rust_builtin.c
@@ -47,7 +47,8 @@ extern char **environ;
 #endif
 #endif
 
-#if defined(__FreeBSD__) || defined(__linux__) || defined(__ANDROID__) || defined(__DragonFly__) || defined(__OpenBSD__)
+#if defined(__FreeBSD__) || defined(__linux__) || defined(__ANDROID__) \
+  || defined(__DragonFly__) || defined(__OpenBSD__)
 extern char **environ;
 #endif
 
@@ -235,7 +236,7 @@ const char * rust_load_self() {
 
         /* get realpath if possible */
         if ((argv[0] != NULL) && ((*argv[0] == '.') || (*argv[0] == '/')
-				|| (strstr(argv[0], "/") != NULL)))
+                                || (strstr(argv[0], "/") != NULL)))
 
             self = realpath(argv[0], NULL);
         else
diff --git a/src/test/run-make/c-dynamic-dylib/cfoo.c b/src/test/run-make/c-dynamic-dylib/cfoo.c
index 9fe07f82f9e..113717a776a 100644
--- a/src/test/run-make/c-dynamic-dylib/cfoo.c
+++ b/src/test/run-make/c-dynamic-dylib/cfoo.c
@@ -1 +1,2 @@
+// ignore-license
 int foo() { return 0; }
diff --git a/src/test/run-make/c-dynamic-rlib/cfoo.c b/src/test/run-make/c-dynamic-rlib/cfoo.c
index 9fe07f82f9e..113717a776a 100644
--- a/src/test/run-make/c-dynamic-rlib/cfoo.c
+++ b/src/test/run-make/c-dynamic-rlib/cfoo.c
@@ -1 +1,2 @@
+// ignore-license
 int foo() { return 0; }
diff --git a/src/test/run-make/c-link-to-rust-dylib/bar.c b/src/test/run-make/c-link-to-rust-dylib/bar.c
index bb4036b06e1..5729d411c5b 100644
--- a/src/test/run-make/c-link-to-rust-dylib/bar.c
+++ b/src/test/run-make/c-link-to-rust-dylib/bar.c
@@ -1,3 +1,4 @@
+// ignore-license
 void foo();
 
 int main() {
diff --git a/src/test/run-make/c-link-to-rust-staticlib/bar.c b/src/test/run-make/c-link-to-rust-staticlib/bar.c
index bb4036b06e1..5729d411c5b 100644
--- a/src/test/run-make/c-link-to-rust-staticlib/bar.c
+++ b/src/test/run-make/c-link-to-rust-staticlib/bar.c
@@ -1,3 +1,4 @@
+// ignore-license
 void foo();
 
 int main() {
diff --git a/src/test/run-make/c-static-dylib/cfoo.c b/src/test/run-make/c-static-dylib/cfoo.c
index 9fe07f82f9e..113717a776a 100644
--- a/src/test/run-make/c-static-dylib/cfoo.c
+++ b/src/test/run-make/c-static-dylib/cfoo.c
@@ -1 +1,2 @@
+// ignore-license
 int foo() { return 0; }
diff --git a/src/test/run-make/c-static-rlib/cfoo.c b/src/test/run-make/c-static-rlib/cfoo.c
index 9fe07f82f9e..113717a776a 100644
--- a/src/test/run-make/c-static-rlib/cfoo.c
+++ b/src/test/run-make/c-static-rlib/cfoo.c
@@ -1 +1,2 @@
+// ignore-license
 int foo() { return 0; }
diff --git a/src/test/run-make/extern-fn-generic/test.c b/src/test/run-make/extern-fn-generic/test.c
index f23dd1eb146..f9faef64afc 100644
--- a/src/test/run-make/extern-fn-generic/test.c
+++ b/src/test/run-make/extern-fn-generic/test.c
@@ -1,16 +1,17 @@
+// ignore-license
 #include <stdint.h>
 
 typedef struct TestStruct {
-	uint8_t x;
-	int32_t y;
+        uint8_t x;
+        int32_t y;
 } TestStruct;
 
 typedef int callback(TestStruct s);
 
 uint32_t call(callback *c) {
-	TestStruct s;
-	s.x = 'a';
-	s.y = 3;
+        TestStruct s;
+        s.x = 'a';
+        s.y = 3;
 
-	return c(s);
+        return c(s);
 }
diff --git a/src/test/run-make/extern-fn-mangle/test.c b/src/test/run-make/extern-fn-mangle/test.c
index 8d93917ade0..1a9855dedec 100644
--- a/src/test/run-make/extern-fn-mangle/test.c
+++ b/src/test/run-make/extern-fn-mangle/test.c
@@ -1,8 +1,9 @@
+// ignore-license
 #include <stdint.h>
 
 uint32_t foo();
 uint32_t bar();
 
 uint32_t add() {
-	return foo() + bar();
+        return foo() + bar();
 }
diff --git a/src/test/run-make/extern-fn-with-packed-struct/test.c b/src/test/run-make/extern-fn-with-packed-struct/test.c
index c3456a64b9b..121e48e84e4 100644
--- a/src/test/run-make/extern-fn-with-packed-struct/test.c
+++ b/src/test/run-make/extern-fn-with-packed-struct/test.c
@@ -1,3 +1,4 @@
+// ignore-license
 // Pragma needed cause of gcc bug on windows: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52991
 #pragma pack(1)
 struct __attribute__((packed)) Foo {
diff --git a/src/test/run-make/extern-fn-with-union/test.c b/src/test/run-make/extern-fn-with-union/test.c
index 86cb6453723..8c87c230693 100644
--- a/src/test/run-make/extern-fn-with-union/test.c
+++ b/src/test/run-make/extern-fn-with-union/test.c
@@ -1,3 +1,4 @@
+// ignore-license
 #include <stdio.h>
 #include <stdint.h>
 
diff --git a/src/test/run-make/interdependent-c-libraries/bar.c b/src/test/run-make/interdependent-c-libraries/bar.c
index 812c9753528..c761f029eff 100644
--- a/src/test/run-make/interdependent-c-libraries/bar.c
+++ b/src/test/run-make/interdependent-c-libraries/bar.c
@@ -1,3 +1,4 @@
+// ignore-license
 void foo();
 
 void bar() { foo(); }
diff --git a/src/test/run-make/interdependent-c-libraries/foo.c b/src/test/run-make/interdependent-c-libraries/foo.c
index 85e6cd8c390..2895ad473bf 100644
--- a/src/test/run-make/interdependent-c-libraries/foo.c
+++ b/src/test/run-make/interdependent-c-libraries/foo.c
@@ -1 +1,2 @@
+// ignore-license
 void foo() {}
diff --git a/src/test/run-make/issue-12446/foo.c b/src/test/run-make/issue-12446/foo.c
index a58cd8bb7c9..186a0046e80 100644
--- a/src/test/run-make/issue-12446/foo.c
+++ b/src/test/run-make/issue-12446/foo.c
@@ -1 +1,2 @@
+// ignore-license
 void some_c_symbol() {}
diff --git a/src/test/run-make/issue-15460/foo.c b/src/test/run-make/issue-15460/foo.c
index 85e6cd8c390..2895ad473bf 100644
--- a/src/test/run-make/issue-15460/foo.c
+++ b/src/test/run-make/issue-15460/foo.c
@@ -1 +1,2 @@
+// ignore-license
 void foo() {}
diff --git a/src/test/run-make/link-path-order/correct.c b/src/test/run-make/link-path-order/correct.c
index 3064af952f8..a595939f92e 100644
--- a/src/test/run-make/link-path-order/correct.c
+++ b/src/test/run-make/link-path-order/correct.c
@@ -1 +1,2 @@
+// ignore-license
 int should_return_one() { return 1; }
diff --git a/src/test/run-make/link-path-order/wrong.c b/src/test/run-make/link-path-order/wrong.c
index 64275b3ad6b..c53e7e3c48c 100644
--- a/src/test/run-make/link-path-order/wrong.c
+++ b/src/test/run-make/link-path-order/wrong.c
@@ -1 +1,2 @@
+// ignore-license
 int should_return_one() { return 0; }
diff --git a/src/test/run-make/linkage-attr-on-static/foo.c b/src/test/run-make/linkage-attr-on-static/foo.c
index 78a6934f57f..d7d33ea12e8 100644
--- a/src/test/run-make/linkage-attr-on-static/foo.c
+++ b/src/test/run-make/linkage-attr-on-static/foo.c
@@ -1,3 +1,4 @@
+// ignore-license
 #include <stdint.h>
 
 extern int32_t BAZ;
diff --git a/src/test/run-make/lto-smoke-c/bar.c b/src/test/run-make/lto-smoke-c/bar.c
index bb4036b06e1..5729d411c5b 100644
--- a/src/test/run-make/lto-smoke-c/bar.c
+++ b/src/test/run-make/lto-smoke-c/bar.c
@@ -1,3 +1,4 @@
+// ignore-license
 void foo();
 
 int main() {
diff --git a/src/test/run-make/manual-link/bar.c b/src/test/run-make/manual-link/bar.c
index e4259998678..3c167b45af9 100644
--- a/src/test/run-make/manual-link/bar.c
+++ b/src/test/run-make/manual-link/bar.c
@@ -1 +1,2 @@
+// ignore-license
 void bar() {}
diff --git a/src/test/run-make/manual-link/foo.c b/src/test/run-make/manual-link/foo.c
index e4259998678..3c167b45af9 100644
--- a/src/test/run-make/manual-link/foo.c
+++ b/src/test/run-make/manual-link/foo.c
@@ -1 +1,2 @@
+// ignore-license
 void bar() {}
diff --git a/src/test/run-make/no-duplicate-libs/bar.c b/src/test/run-make/no-duplicate-libs/bar.c
index 330d914a011..a7b02a2f10b 100644
--- a/src/test/run-make/no-duplicate-libs/bar.c
+++ b/src/test/run-make/no-duplicate-libs/bar.c
@@ -1,3 +1,4 @@
+// ignore-license
 extern void foo();
 
 void bar() { foo(); }
diff --git a/src/test/run-make/no-duplicate-libs/foo.c b/src/test/run-make/no-duplicate-libs/foo.c
index 85e6cd8c390..2895ad473bf 100644
--- a/src/test/run-make/no-duplicate-libs/foo.c
+++ b/src/test/run-make/no-duplicate-libs/foo.c
@@ -1 +1,2 @@
+// ignore-license
 void foo() {}