Make copy of <bits/std_abs.h> from GCC 7 [BZ #21573]

<bits/std_abs.h> from GCC 7 will include /usr/include/stdlib.h from
"#include_next" (instead of stdlib/stdlib.h in the glibc source
directory), and this turns up as a make dependency.  Also make a copy
of <bits/std_abs.h> to prevent it from including /usr/include/stdlib.h.

	[BZ #21573]
	* Makerules [$(c++-bits-std_abs-h) != ""] (before-compile): Add
	$(common-objpfx)bits/std_abs.h.
	[$(c++-bits-std_abs-h) != ""] ($(common-objpfx)bits/std_abs.h):
	New target.
	* config.make.in (c++-bits-std_abs-h): New.
	* configure.ac (find_cxx_header): Use "\,$1," with sed.
	(CXX_BITS_STD_ABS_H): New.
	(AC_SUBST(CXX_BITS_STD_ABS_H)): Likewise.
	* configure: Regenerated.

(cherry picked from commit a65ea28d1833d3502c5070472e43bda04410e6b5)

4 files changed, 16 insertions, 2 deletions

diff --git a/Makerules b/Makerules
index 7f0eef8096..8210a452b8 100644
--- a/Makerules
+++ b/Makerules
@@ -127,6 +127,14 @@ $(common-objpfx)cstdlib: $(c++-cstdlib-header)
 $(common-objpfx)cmath: $(c++-cmath-header)
 	$(INSTALL_DATA) $< $@T
 	$(move-if-change) $@T $@
+ifneq (,$(c++-bits-std_abs-h))
+# Also make a copy of <bits/std_abs.h> from GCC 7 to prevent it from
+# including /usr/include/stdlib.h.
+before-compile := $(common-objpfx)bits/std_abs.h $(before-compile)
+$(common-objpfx)bits/std_abs.h: $(c++-bits-std_abs-h)
+	$(INSTALL_DATA) $< $@T
+	$(move-if-change) $@T $@
+endif
 endif
 
 before-compile := $(common-objpfx)libc-abis.h $(before-compile)
diff --git a/config.make.in b/config.make.in
index 5836b32a72..709527da4f 100644
--- a/config.make.in
+++ b/config.make.in
@@ -47,6 +47,7 @@ sysincludes = @SYSINCLUDES@
 c++-sysincludes = @CXX_SYSINCLUDES@
 c++-cstdlib-header = @CXX_CSTDLIB_HEADER@
 c++-cmath-header = @CXX_CMATH_HEADER@
+c++-bits-std_abs-h = @CXX_BITS_STD_ABS_H@
 all-warnings = @all_warnings@
 enable-werror = @enable_werror@
 
diff --git a/configure b/configure
index eecd0ace74..9158a7d207 100755
--- a/configure
+++ b/configure
@@ -634,6 +634,7 @@ BISON
 INSTALL_INFO
 PERL
 BASH_SHELL
+CXX_BITS_STD_ABS_H
 CXX_CMATH_HEADER
 CXX_CSTDLIB_HEADER
 CXX_SYSINCLUDES
@@ -5318,14 +5319,16 @@ fi
 # copy of those headers in Makerules.
 if test -n "$CXX"; then
   find_cxx_header () {
-    echo "#include <$1>" | $CXX -M -MP -x c++ - | sed -n "/$1:/{s/:\$//;p}"
+    echo "#include <$1>" | $CXX -M -MP -x c++ - | sed -n "\,$1:,{s/:\$//;p}"
   }
   CXX_CSTDLIB_HEADER="$(find_cxx_header cstdlib)"
   CXX_CMATH_HEADER="$(find_cxx_header cmath)"
+  CXX_BITS_STD_ABS_H="$(find_cxx_header bits/std_abs.h)"
 fi
 
 
 
+
 # Test if LD_LIBRARY_PATH contains the notation for the current directory
 # since this would lead to problems installing/building glibc.
 # LD_LIBRARY_PATH contains the current directory if one of the following
diff --git a/configure.ac b/configure.ac
index 4a77411b71..789283ebd7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1176,13 +1176,15 @@ AC_SUBST(CXX_SYSINCLUDES)
 # copy of those headers in Makerules.
 if test -n "$CXX"; then
   find_cxx_header () {
-    echo "#include <$1>" | $CXX -M -MP -x c++ - | sed -n "/$1:/{s/:\$//;p}"
+    echo "#include <$1>" | $CXX -M -MP -x c++ - | sed -n "\,$1:,{s/:\$//;p}"
   }
   CXX_CSTDLIB_HEADER="$(find_cxx_header cstdlib)"
   CXX_CMATH_HEADER="$(find_cxx_header cmath)"
+  CXX_BITS_STD_ABS_H="$(find_cxx_header bits/std_abs.h)"
 fi
 AC_SUBST(CXX_CSTDLIB_HEADER)
 AC_SUBST(CXX_CMATH_HEADER)
+AC_SUBST(CXX_BITS_STD_ABS_H)
 
 # Test if LD_LIBRARY_PATH contains the notation for the current directory
 # since this would lead to problems installing/building glibc.