The purpose of these headers is to fix issues with mingw v4.0, as described in #9246.

This works by adding this directory to GCC include search path before mingw system headers directories,
so we can intercept their inclusions and add missing definitions without having to modify files in mingw/include.

7 files changed, 38 insertions, 3 deletions

diff --git a/mk/llvm.mk b/mk/llvm.mk
index 9e024ffa9f4..9de04bed598 100644
--- a/mk/llvm.mk
+++ b/mk/llvm.mk
@@ -28,7 +28,7 @@ LLVM_STAMP_$(1) = $$(CFG_LLVM_BUILD_DIR_$(1))/llvm-auto-clean-stamp
 
 $$(LLVM_CONFIG_$(1)): $$(LLVM_DEPS) $$(LLVM_STAMP_$(1))
 	@$$(call E, make: llvm)
-	$$(Q)$$(MAKE) -C $$(CFG_LLVM_BUILD_DIR_$(1)) $$(CFG_LLVM_BUILD_ENV)
+	$$(Q)$$(MAKE) -C $$(CFG_LLVM_BUILD_DIR_$(1)) $$(CFG_LLVM_BUILD_ENV_$(1))
 	$$(Q)touch $$(LLVM_CONFIG_$(1))
 endif
 
diff --git a/mk/platform.mk b/mk/platform.mk
index ac6cf3c5451..c2fe8e98e45 100644
--- a/mk/platform.mk
+++ b/mk/platform.mk
@@ -352,7 +352,7 @@ AR_i686-pc-mingw32=$(AR)
 CFG_LIB_NAME_i686-pc-mingw32=$(1).dll
 CFG_LIB_GLOB_i686-pc-mingw32=$(1)-*.dll
 CFG_LIB_DSYM_GLOB_i686-pc-mingw32=$(1)-*.dylib.dSYM
-CFG_GCCISH_CFLAGS_i686-pc-mingw32 := -Wall -Werror -g -m32 -march=i686 -D_WIN32_WINNT=0x0600
+CFG_GCCISH_CFLAGS_i686-pc-mingw32 := -Wall -Werror -g -m32 -march=i686 -D_WIN32_WINNT=0x0600 -I$(CFG_SRC_DIR)src/etc/mingw-fix-include
 CFG_GCCISH_CXXFLAGS_i686-pc-mingw32 := -fno-rtti
 CFG_GCCISH_LINK_FLAGS_i686-pc-mingw32 := -shared -fPIC -g -m32
 CFG_GCCISH_DEF_FLAG_i686-pc-mingw32 :=
@@ -361,6 +361,7 @@ CFG_GCCISH_POST_LIB_FLAGS_i686-pc-mingw32 :=
 CFG_DEF_SUFFIX_i686-pc-mingw32 := .mingw32.def
 CFG_INSTALL_NAME_i686-pc-mingw32 =
 CFG_LIBUV_LINK_FLAGS_i686-pc-mingw32 := -lWs2_32 -lpsapi -liphlpapi
+CFG_LLVM_BUILD_ENV_i686-pc-mingw32 := CPATH=$(CFG_SRC_DIR)src/etc/mingw-fix-include
 CFG_EXE_SUFFIX_i686-pc-mingw32 := .exe
 CFG_WINDOWSY_i686-pc-mingw32 := 1
 CFG_UNIXY_i686-pc-mingw32 :=
diff --git a/mk/rt.mk b/mk/rt.mk
index 35ee42f9cb4..daaf313e01b 100644
--- a/mk/rt.mk
+++ b/mk/rt.mk
@@ -24,7 +24,7 @@
 # working under these assumptions).
 
 # Hack for passing flags into LIBUV, see below.
-LIBUV_FLAGS_i386 = -m32 -fPIC
+LIBUV_FLAGS_i386 = -m32 -fPIC -I$(S)src/etc/mingw-fix-include
 LIBUV_FLAGS_x86_64 = -m64 -fPIC
 ifeq ($(OSTYPE_$(1)), linux-androideabi)
 LIBUV_FLAGS_arm = -fPIC -DANDROID -std=gnu99
diff --git a/src/etc/mingw-fix-include/README.txt b/src/etc/mingw-fix-include/README.txt
new file mode 100644
index 00000000000..876db17a248
--- /dev/null
+++ b/src/etc/mingw-fix-include/README.txt
@@ -0,0 +1,6 @@
+The purpose of these headers is to fix issues with mingw v4.0, as described in #9246.
+
+This works by adding this directory to GCC include search path before mingw system headers directories, 
+so we can intercept their inclusions and add missing definitions without having to modify files in mingw/include.
+
+Once mingw fixes all 3 issues mentioned in #9246, this directory and all references to it from rust/mk/* may be removed.
diff --git a/src/etc/mingw-fix-include/bits/c++config.h b/src/etc/mingw-fix-include/bits/c++config.h
new file mode 100644
index 00000000000..4520779e275
--- /dev/null
+++ b/src/etc/mingw-fix-include/bits/c++config.h
@@ -0,0 +1,8 @@
+#ifndef _FIX_CXXCONFIG_H
+#define _FIX_CXXCONFIG_H 1
+
+#define _GLIBCXX_HAVE_FENV_H 1
+
+#include_next <bits/c++config.h>
+
+#endif
diff --git a/src/etc/mingw-fix-include/winbase.h b/src/etc/mingw-fix-include/winbase.h
new file mode 100644
index 00000000000..3be26d1cb34
--- /dev/null
+++ b/src/etc/mingw-fix-include/winbase.h
@@ -0,0 +1,8 @@
+#ifndef _FIX_WINBASE_H
+#define _FIX_WINBASE_H 1
+
+#define NTDDK_VERSION NTDDI_VERSION
+
+#include_next <winbase.h>
+
+#endif
diff --git a/src/etc/mingw-fix-include/winsock2.h b/src/etc/mingw-fix-include/winsock2.h
new file mode 100644
index 00000000000..36b58dcd1ee
--- /dev/null
+++ b/src/etc/mingw-fix-include/winsock2.h
@@ -0,0 +1,12 @@
+#ifndef _FIX_WINSOCK2_H
+#define _FIX_WINSOCK2_H 1
+
+#include_next <winsock2.h>
+
+typedef struct pollfd {
+  SOCKET fd;
+  short  events;
+  short  revents;
+} WSAPOLLFD, *PWSAPOLLFD, *LPWSAPOLLFD;
+
+#endif