gcc: update to allow compiling different versions

[feed/packages.git] / devel / gcc / patches / 11.2.0 / 980-add-nostdinc++.patch

diff --git a/devel/gcc/patches/11.2.0/980-add-nostdinc++.patch b/devel/gcc/patches/11.2.0/980-add-nostdinc++.patch
new file mode 100644 (file)
index 0000000..c1fe3e5
--- /dev/null
+++ b/devel/gcc/patches/11.2.0/980-add-nostdinc++.patch
@@ -0,0 +1,73 @@
+From: Jonathan Wakely <jwakely@redhat.com>
+Date: Fri, 7 Jan 2022 15:21:03 +0000 (+0000)
+Subject: libstdc++: Add -nostdinc++ for c++17 sources [PR100017]
+X-Git-Tag: releases/gcc-11.3.0~445
+X-Git-Url: https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff_plain;h=01a70ccd723eb9a479186fe37c972b0d0f8676cf
+
+libstdc++: Add -nostdinc++ for c++17 sources [PR100017]
+
+When building a build!=host compiler, the just-built gcc can't be used
+to build the target libstdc++ (because it is built for the host triplet,
+not the build triplet). The top-level configure.ac sets up the build
+flags for libstdc++ (and other "raw_cxx" libs) like this:
+
+GCC_TARGET_TOOL(c++ for libstdc++, RAW_CXX_FOR_TARGET, CXX,
+               [gcc/xgcc -shared-libgcc -B$$r/$(HOST_SUBDIR)/gcc -nostdinc++ -L$$r/$(TARGET_SUBDIR)/libstdc++-v3/src -L$$r/$(TARGET_SUBDIR)/libstdc++-v3/src/.libs -L$$r/$(TARGET_SUBDIR)/libstdc++-v3/libsupc++/.libs],
+               c++)
+
+The -nostdinc++ flag is only used for the IN-TREE-TOOL, i.e. when using
+the just-built gcc/xgcc compiler. This means that the cross-compiler
+used to build libstdc++ will add its own libstdc++ headers to the
+include path. That results in the #include <cfenv> in
+src/c++17/floating_to_chars.cc and src/c++17/floating_from_chars.cc
+doing #include_next <fenv.h> and finding the libstdc++ fenv.h wrapper
+from the host compiler. Because that has the same include guard as the
+<fenv.h> in the libstdc++ we're trying to build, we never reach the
+underlying <fenv.h> from libc. That results in several errors of the
+form:
+
+error: 'fenv_t' has not been declared in '::'
+
+The most correct fix would be to add -nostdinc++ to the
+RAW_CXX_FOR_TARGET variable in configure.ac, or the
+RAW_CXX_TARGET_EXPORTS variable in Makefile.tpl.
+
+Another solution would be to make the libstdc++ <fenv.h> wrapper use
+_GLIBCXX_INCLUDE_NEXT_C_HEADERS like our <stdlib.h> and other C header
+wrappers.
+
+For now though, the simplest and safest solution is to just add
+-nostdinc++ to the CXXFLAGS used for src/c++17/*.cc, which is what this
+does.
+
+libstdc++-v3/ChangeLog:
+
+       PR libstdc++/100017
+       * src/c++17/Makefile.am (AM_CXXFLAGS): Add -nostdinc++.
+       * src/c++17/Makefile.in: Regenerate.
+
+(cherry picked from commit 4fde88e5dd152fe866a97b12e0f8229970d15cb3)
+---
+
+--- a/libstdc++-v3/src/c++17/Makefile.am
++++ b/libstdc++-v3/src/c++17/Makefile.am
+@@ -79,7 +79,7 @@ endif
+ # OPTIMIZE_CXXFLAGS on the compile line so that -O2 can be overridden
+ # as the occasion calls for it.
+ AM_CXXFLAGS = \
+-      -std=gnu++17 \
++      -std=gnu++17 -nostdinc++ \
+       $(glibcxx_lt_pic_flag) $(glibcxx_compiler_shared_flag) \
+       $(XTEMPLATE_FLAGS) $(VTV_CXXFLAGS) \
+       $(WARN_CXXFLAGS) $(OPTIMIZE_CXXFLAGS) $(CONFIG_CXXFLAGS) \
+--- a/libstdc++-v3/src/c++17/Makefile.in
++++ b/libstdc++-v3/src/c++17/Makefile.in
+@@ -455,7 +455,7 @@ libc__17convenience_la_SOURCES = $(sourc
+ # OPTIMIZE_CXXFLAGS on the compile line so that -O2 can be overridden
+ # as the occasion calls for it.
+ AM_CXXFLAGS = \
+-      -std=gnu++17 \
++      -std=gnu++17 -nostdinc++ \
+       $(glibcxx_lt_pic_flag) $(glibcxx_compiler_shared_flag) \
+       $(XTEMPLATE_FLAGS) $(VTV_CXXFLAGS) \
+       $(WARN_CXXFLAGS) $(OPTIMIZE_CXXFLAGS) $(CONFIG_CXXFLAGS) \