[patch] libstdc++/69581 Don't define guard macros when doing #include_next in math.h and stdlib.h

[patch] libstdc++/69581 Don't define guard macros when doing #include_next in math.h and stdlib.h

[Jonathan Wakely]

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The new <math.h> and <stdlib.h> wrapper headers should not define
their guard macros when being included in "pass-through" mode, i.e.
when _GLIBCXX_INCLUDE_NEXT_C_HEADERS is defined. This patch allows the
wrapper to pass-through as many layers of wrapper headers as needed
until the real C library header is found.

Tested powerpc64-linux, committed to trunk.


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commit c501dcd83400039b74f79f338580f25e148556ac
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon Feb 1 10:53:35 2016 +0000

    Don't define guard macros when doing #include_next in math.h and stdlib.h
    
    2016-02-01  Bernd Edlinger  <bernd.edlinger@hotmail.de>
    
    	PR libstdc++/69581
    	* include/c_compatibility/math.h: Move header guards.
    	* include/c_compatibility/stdlib.h: Likewise.

diff --git a/libstdc++-v3/include/c_compatibility/math.h b/libstdc++-v3/include/c_compatibility/math.h
index 243e631..1f579ee 100644
--- a/libstdc++-v3/include/c_compatibility/math.h
+++ b/libstdc++-v3/include/c_compatibility/math.h
@@ -26,13 +26,13 @@
  *  This is a Standard C++ Library header.
  */
 
+#if !defined __cplusplus || defined _GLIBCXX_INCLUDE_NEXT_C_HEADERS
+# include_next <math.h>
+#else
 
 #ifndef _GLIBCXX_MATH_H
 #define _GLIBCXX_MATH_H 1
 
-#if !defined __cplusplus || defined _GLIBCXX_INCLUDE_NEXT_C_HEADERS
-# include_next <math.h>
-#else
 # include <cmath>
 
 using std::abs;
@@ -177,7 +177,5 @@ using std::sph_neumannl;
 using std::sph_neumann;
 #endif // __STDCPP_WANT_MATH_SPEC_FUNCS__
 
-#endif // __cplusplus
-
 #endif // _GLIBCXX_MATH_H
-
+#endif // __cplusplus
diff --git a/libstdc++-v3/include/c_compatibility/stdlib.h b/libstdc++-v3/include/c_compatibility/stdlib.h
index 31e7e5f..747ad76 100644
--- a/libstdc++-v3/include/c_compatibility/stdlib.h
+++ b/libstdc++-v3/include/c_compatibility/stdlib.h
@@ -26,12 +26,13 @@
  *  This is a Standard C++ Library header.
  */
 
-#ifndef _GLIBCXX_STDLIB_H
-#define _GLIBCXX_STDLIB_H 1
-
 #if !defined __cplusplus || defined _GLIBCXX_INCLUDE_NEXT_C_HEADERS
 # include_next <stdlib.h>
 #else
+
+#ifndef _GLIBCXX_STDLIB_H
+#define _GLIBCXX_STDLIB_H 1
+
 # include <cstdlib>
 
 using std::abort;
@@ -81,5 +82,5 @@ using std::wctomb;
 #endif // _GLIBCXX_USE_WCHAR_T
 #endif
 
-#endif
-#endif
+#endif // _GLIBCXX_STDLIB_H
+#endif // __cplusplus