commit 8e2f7c68111ba8fae795ee08b6822e21ab8cfa38
Author: Joseph Myers <joseph@codesourcery.com>
Date:   Wed Oct 21 15:14:13 2015 +0000

    Use -Wold-style-definition.
    
    This patch makes glibc build with -Wold-style-definition to avoid
    old-style function definitions creeping back in by accident.
    
    Tested for x86_64 and x86 (testsuite, and that installed shared
    libraries are unchanged by the patch).  Also tested build for arm,
    mips64 and powerpc32.  Hopefully there aren't any remaining
    system-specific files with old-style definitions whose formatting
    evaded my searches, but if there are, they will be easy to fix.
    
            * Makeconfig (+gccwarn-c): Add -Wold-style-definition.
            * Makefile ($(objpfx)c++-types-check.out): Filter out
            $(+gccwarn-c) instead of -Wstrict-prototypes.

Conflicts:
	Makefile

Resolved conflict due to missing $(evaluate-test) in the tree (commit
f0881698bf244bcb16c394d2d6258d975a11baef, Generate .test-result files
for tests with special rules.).

diff --git a/Makeconfig b/Makeconfig
index 3c0d4abc5f5f30df..f8313c9774d47522 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -647,7 +647,7 @@ endif
 ifeq ($(enable-werror),yes)
 +gccwarn += -Werror
 endif
-+gccwarn-c = -Wstrict-prototypes
++gccwarn-c = -Wstrict-prototypes -Wold-style-definition
 
 # We do not depend on the address of constants in different files to be
 # actually different, so allow the compiler to merge them all.
diff --git a/Makefile b/Makefile
index bebb0a865a150a3a..f4128c2627dd0bb9 100644
--- a/Makefile
+++ b/Makefile
@@ -279,7 +279,7 @@ ifneq ($(CXX),no)
 vpath c++-types.data $(+sysdep_dirs)
 
 $(objpfx)c++-types-check.out: c++-types.data scripts/check-c++-types.sh
-	scripts/check-c++-types.sh $< $(CXX) $(filter-out -std=gnu99 -Wstrict-prototypes,$(CFLAGS)) $(CPPFLAGS) > $@
+	scripts/check-c++-types.sh $< $(CXX) $(filter-out -std=gnu99 $(+gccwarn-c),$(CFLAGS)) $(CPPFLAGS) > $@
 endif
 
 $(objpfx)check-local-headers.out: scripts/check-local-headers.sh