buildroot

Allow C99-depending features of libstdc++ with uClibc

​

The libstdc++ code is fairly restrictive on how it checks for C99

compatibility: it requires *complete* C99 support to enable certain

features. For example, uClibc provides a good number of C99 features,

but not C99 complex number support. For this reason, libstdc++

completely disables many the standard C++ methods that can in fact

work because uClibc provides the necessary functions.

​

This patch is similar and highly inspired from

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58393, but implemented in

a way that doesn't involve changing the configure.ac script, as

autoreconfiguring gcc is complicated. It simply relies on the fact

that uClibc defines the __UCLIBC__ definition.

​

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

[Gustavo: update for 4.9.3]

​

diff -Nura gcc-4.9.3.orig/libstdc++-v3/config/locale/generic/c_locale.h gcc-4.9.3/libstdc++-v3/config/locale/generic/c_locale.h

--- gcc-4.9.3.orig/libstdc++-v3/config/locale/generic/c_locale.h    2014-01-02 19:30:10.000000000 -0300

+++ gcc-4.9.3/libstdc++-v3/config/locale/generic/c_locale.h 2015-06-27 06:46:04.420022179 -0300

@@ -70,7 +70,7 @@

     __builtin_va_list __args;

     __builtin_va_start(__args, __fmt);

-#ifdef _GLIBCXX_USE_C99

+#if defined(_GLIBCXX_USE_C99) || defined(__UCLIBC__)

     const int __ret = __builtin_vsnprintf(__out, __size, __fmt, __args);

 #else

     const int __ret = __builtin_vsprintf(__out, __fmt, __args);

diff -Nura gcc-4.9.3.orig/libstdc++-v3/config/locale/gnu/c_locale.h gcc-4.9.3/libstdc++-v3/config/locale/gnu/c_locale.h

--- gcc-4.9.3.orig/libstdc++-v3/config/locale/gnu/c_locale.h    2014-01-02 19:30:10.000000000 -0300

+++ gcc-4.9.3/libstdc++-v3/config/locale/gnu/c_locale.h 2015-06-27 06:46:04.465023743 -0300

@@ -88,7 +88,7 @@

     __builtin_va_list __args;

     __builtin_va_start(__args, __fmt);

-#ifdef _GLIBCXX_USE_C99

+#if defined(_GLIBCXX_USE_C99) || defined(__UCLIBC__)

     const int __ret = __builtin_vsnprintf(__out, __size, __fmt, __args);

 #else

     const int __ret = __builtin_vsprintf(__out, __fmt, __args);

diff -Nura gcc-4.9.3.orig/libstdc++-v3/include/bits/basic_string.h gcc-4.9.3/libstdc++-v3/include/bits/basic_string.h

--- gcc-4.9.3.orig/libstdc++-v3/include/bits/basic_string.h 2015-05-28 13:27:46.000000000 -0300

+++ gcc-4.9.3/libstdc++-v3/include/bits/basic_string.h  2015-06-27 06:49:04.741284648 -0300

@@ -2844,7 +2844,7 @@

 _GLIBCXX_END_NAMESPACE_VERSION

 } // namespace

-#if __cplusplus >= 201103L && defined(_GLIBCXX_USE_C99)

+#if __cplusplus >= 201103L && (defined(_GLIBCXX_USE_C99) || defined(__UCLIBC__))

 #include <ext/string_conversions.h>

diff -Nura gcc-4.9.3.orig/libstdc++-v3/include/bits/locale_facets_nonio.tcc gcc-4.9.3/libstdc++-v3/include/bits/locale_facets_nonio.tcc

--- gcc-4.9.3.orig/libstdc++-v3/include/bits/locale_facets_nonio.tcc    2014-01-02 19:30:10.000000000 -0300

+++ gcc-4.9.3/libstdc++-v3/include/bits/locale_facets_nonio.tcc 2015-06-27 06:46:04.466023777 -0300

@@ -572,7 +572,7 @@

     {

       const locale __loc = __io.getloc();

       const ctype<_CharT>& __ctype = use_facet<ctype<_CharT> >(__loc);

-#ifdef _GLIBCXX_USE_C99

+#if defined(_GLIBCXX_USE_C99) || defined(__UCLIBC__)