[gcc r10-6049] libstdc++: Fix freestanding build PR 92376)

[Jonathan Wakely]

https://gcc.gnu.org/g:0ba6a850b597236832140bf57bf6083b6fab93f9

commit r10-6049-g0ba6a850b597236832140bf57bf6083b6fab93f9
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Jan 17 15:49:02 2020 +0000

    libstdc++: Fix freestanding build PR 92376)
    
    In a freestanding library we don't install the <pstl/pstl_config.h>
    header, so don't try to include it unless it exists.
    
    Explicitly declare aligned alloc functions for freestanding, because
    <cstdlib> doesn't declare them.
    
    	PR libstdc++/92376
    	* include/bits/c++config: Only do PSTL config when the header is
    	present, to fix freestanding.
    	* libsupc++/new_opa.cc [!_GLIBCXX_HOSTED]: Declare allocation
    	functions if they were detected by configure.

Diff:
---
 libstdc++-v3/ChangeLog              |  8 ++++++++
 libstdc++-v3/include/bits/c++config |  5 ++++-
 libstdc++-v3/libsupc++/new_opa.cc   | 15 +++++++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index c37d3b1..f0d3b1c 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,11 @@
+2020-01-17  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/92376
+	* include/bits/c++config: Only do PSTL config when the header is
+	present, to fix freestanding.
+	* libsupc++/new_opa.cc [!_GLIBCXX_HOSTED]: Declare allocation
+	functions if they were detected by configure.
+
 2020-01-16  Kai-Uwe Eckhardt  <kuehro@gmx.de>
 	    Matthew Bauer  <mjbauer95@gmail.com>
 	    Jonathan Wakely  <jwakely@redhat.com>
diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
index 875a5e7..b1fad59 100644
--- a/libstdc++-v3/include/bits/c++config
+++ b/libstdc++-v3/include/bits/c++config
@@ -666,6 +666,8 @@ namespace std
 // PSTL configuration
 
 #if __cplusplus >= 201703L
+// This header is not installed for freestanding:
+#if __has_include(<pstl/pstl_config.h>)
 // Preserved here so we have some idea which version of upstream we've pulled in
 // #define PSTL_VERSION 9000
 
@@ -684,6 +686,7 @@ namespace std
 # define _PSTL_ASSERT_MSG(_Condition, _Message) __glibcxx_assert(_Condition)
 
 #include <pstl/pstl_config.h>
+#endif // __has_include
+#endif // C++17
 
-#endif
 // End of prewritten config; the settings discovered at configure time follow.
diff --git a/libstdc++-v3/libsupc++/new_opa.cc b/libstdc++-v3/libsupc++/new_opa.cc
index 4e36fbf..8fac193 100644
--- a/libstdc++-v3/libsupc++/new_opa.cc
+++ b/libstdc++-v3/libsupc++/new_opa.cc
@@ -43,6 +43,21 @@ extern "C" void *memalign(std::size_t boundary, std::size_t size);
 using std::new_handler;
 using std::bad_alloc;
 
+#if ! _GLIBCXX_HOSTED
+extern "C"
+{
+# if _GLIBCXX_HAVE_ALIGNED_ALLOC
+  void *aligned_alloc(size_t alignment, size_t size);
+# elif _GLIBCXX_HAVE__ALIGNED_MALLOC
+  void *_aligned_malloc(size_t size, size_t alignment);
+# elif _GLIBCXX_HAVE_POSIX_MEMALIGN
+  void *posix_memalign(void **, size_t alignment, size_t size);
+# elif _GLIBCXX_HAVE_MEMALIGN
+  void *memalign(size_t alignment, size_t size);
+# endif
+}
+#endif
+
 namespace __gnu_cxx {
 #if _GLIBCXX_HAVE_ALIGNED_ALLOC
 using ::aligned_alloc;