[fix] ensure gcc 4.8 compat header is installed

re #103

CMakeLists.txt

@@ -35,6 +35,7 @@ set(C4CORE_SRC_FILES
     c4/export.hpp
     c4/format.hpp
     c4/format.cpp
+    c4/gcc-4.8.hpp
     c4/hash.hpp
     c4/language.hpp
     c4/language.cpp

changelog/current.md

@@ -49,8 +49,9 @@ assert(to_substr((char*)ptr).len == 3); // as before
 
 - [PR#115](https://github.com/biojppm/c4core/pull/115) - Refactor of `c4::blob`/`c4::cblob`. Use SFINAE to invalidate some of the constructors.
 - [PR#110](https://github.com/biojppm/c4core/pull/110)/[PR#107](https://github.com/biojppm/c4core/pull/107) - Update fast_float.
-- [PR#108](https://github.com/biojppm/c4core/pull/108) - Fix preprocessor pasting of strings in `C4_NOT_IMPLEMENTED_MSG()` and `C4_NOT_IMPLEMENTED_IF_MSG()`.
+- [PR#108](https://github.com/biojppm/c4core/pull/108) - Fix preprocessor concatenation of strings in `C4_NOT_IMPLEMENTED_MSG()` and `C4_NOT_IMPLEMENTED_IF_MSG()`.
 - [PR#106](https://github.com/biojppm/c4core/pull/106) - Fix include guard in the gcc 4.8 compatibility header, causing it to be missing from the amalgamated header.
+- [PR#123](https://github.com/biojppm/c4core/pull/123) - Ensure the gcc 4.8 compatibility header is installed (fixes [#103](https://github.com/biojppm/c4core/issues/103)).
 - [PR#105](https://github.com/biojppm/c4core/pull/105) - Fix existing throw in `c4/ext/sg14/inplace_function.h`. Ensure tests run with exceptions disabled and RTTI disabled. Add examples of exceptional control flow with `setjmp()/std::longjmp()`.
 - [PR#104](https://github.com/biojppm/c4core/pull/104)/[PR#112](https://github.com/biojppm/c4core/pull/112) - Fix pedantic warnings in gcc, clang and MSVC
 - [PR#104](https://github.com/biojppm/c4core/pull/104) - Fix possible compile error when `__GNUC__` is not defined

src/c4/gcc-4.8.hpp

@@ -0,0 +1,72 @@
+#ifndef _C4_GCC_4_8_HPP_
+#define _C4_GCC_4_8_HPP_
+
+#if __GNUC__ == 4 && __GNUC_MINOR__ >= 8
+/* STL polyfills for old GNU compilers */
+
+_Pragma("GCC diagnostic ignored \"-Wshadow\"")
+_Pragma("GCC diagnostic ignored \"-Wmissing-field-initializers\"")
+
+#if __cplusplus
+#include <cstdint>
+#include <type_traits>
+
+namespace std {
+
+template<typename _Tp>
+struct is_trivially_copyable : public integral_constant<bool,
+    is_destructible<_Tp>::value && __has_trivial_destructor(_Tp) &&
+    (__has_trivial_constructor(_Tp) || __has_trivial_copy(_Tp) || __has_trivial_assign(_Tp))>
+{ };
+
+template<typename _Tp>
+using is_trivially_copy_constructible = has_trivial_copy_constructor<_Tp>;
+
+template<typename _Tp>
+using is_trivially_default_constructible = has_trivial_default_constructor<_Tp>;
+
+template<typename _Tp>
+using is_trivially_copy_assignable = has_trivial_copy_assign<_Tp>;
+
+/* not supported */
+template<typename _Tp>
+struct is_trivially_move_constructible : false_type
+{ };
+
+/* not supported */
+template<typename _Tp>
+struct is_trivially_move_assignable : false_type
+{ };
+
+inline void *align(size_t __align, size_t __size, void*& __ptr, size_t& __space) noexcept
+{
+    if (__space < __size)
+        return nullptr;
+    const auto __intptr = reinterpret_cast<uintptr_t>(__ptr);
+    const auto __aligned = (__intptr - 1u + __align) & -__align;
+    const auto __diff = __aligned - __intptr;
+    if (__diff > (__space - __size))
+        return nullptr;
+    else
+    {
+        __space -= __diff;
+        return __ptr = reinterpret_cast<void*>(__aligned);
+    }
+}
+
+#if __GNUC__ == 4 && __GNUC_MINOR__ == 8
+typedef long double max_align_t ;
+#endif
+
+}
+#else // __cplusplus
+
+#include <string.h>
+// see https://sourceware.org/bugzilla/show_bug.cgi?id=25399 (ubuntu gcc-4.8)
+#define memset(s, c, count) __builtin_memset(s, c, count)
+
+#endif // __cplusplus
+
+#endif // __GNUC__ == 4 && __GNUC_MINOR__ >= 8
+
+#endif // _C4_GCC_4_8_HPP_

tools/amalgamate.py

@@ -68,7 +68,7 @@ def amalgamate_c4core(filename: str,
         "src/c4/platform.hpp",
         "src/c4/cpu.hpp",
         am.injcode(required_gcc4_8_include),
-        "cmake/compat/c4/gcc-4.8.hpp",
+        "src/c4/gcc-4.8.hpp",
         "src/c4/compiler.hpp",
         "src/c4/language.hpp",
         "src/c4/types.hpp",