package/pistache: fix detection of atomic

pistache does not mandatory link with libatomic since
https://github.com/oktal/pistache/commit/4ed3f8e148dae203730139ae3c1c4c87bfc86c02
however the logic is broken because the C language is not enabled

Fixes:
 - http://autobuild.buildroot.org/results/17f05238a3479f5b0c9ef8f9bb42210f6fc14fff

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

diff --git a/package/pistache/0001-CMakeLists.txt-add-C-language-to-project-statement.patch b/package/pistache/0001-CMakeLists.txt-add-C-language-to-project-statement.patch
new file mode 100644 (file)
index 0000000..c393a48
--- /dev/null
+++ b/package/pistache/0001-CMakeLists.txt-add-C-language-to-project-statement.patch
@@ -0,0 +1,70 @@
+From a50fc9bde098e4e89584a5da9f94f620c11b6733 Mon Sep 17 00:00:00 2001
+From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+Date: Sun, 16 Aug 2020 12:31:46 +0200
+Subject: [PATCH] CMakeLists.txt: add C language to project statement
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+This will fix the detection of atomic:
+
+-- Performing Test HAVE_CXX_ATOMICS64_WITHOUT_LIB
+-- Performing Test HAVE_CXX_ATOMICS64_WITHOUT_LIB - Failed
+-- Looking for __atomic_load_8 in atomic
+-- Looking for __atomic_load_8 in atomic - not found
+CMake Error at CMakeModules/CheckAtomic.cmake:76 (message):
+  Host compiler appears to require libatomic for 64-bit operations, but
+  cannot find it.
+Call Stack (most recent call first):
+  CMakeLists.txt:19 (include)
+
+Indeed if C language is not enabled, the test will be run with the C++
+compiler resulting in the following error:
+
+Building CXX object CMakeFiles/cmTC_fad22.dir/CheckFunctionExists.cxx.o
+/tmp/instance-0/output-1/host/bin/mipsel-linux-g++ --sysroot=/tmp/instance-0/output-1/host/mipsel-buildroot-linux-gnu/sysroot    -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -D_FORTIFY_SOURCE=1 -Wall -Wconversion -pedantic -Wextra -Wno-missing-field-initializers -DCHECK_FUNCTION_EXISTS=__atomic_load_8  -DNDEBUG   -o CMakeFiles/cmTC_fad22.dir/CheckFunctionExists.cxx.o -c /tmp/instance-0/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CheckLibraryExists/CheckFunctionExists.cxx
+<command-line>: error: new declaration 'char __atomic_load_8()' ambiguates built-in declaration 'long long unsigned int __atomic_load_8(const volatile void*, int)' [-fpermissive]
+/tmp/instance-0/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CheckLibraryExists/CheckFunctionExists.cxx:7:3: note: in expansion of macro 'CHECK_FUNCTION_EXISTS'
+   CHECK_FUNCTION_EXISTS(void);
+   ^~~~~~~~~~~~~~~~~~~~~
+/tmp/instance-0/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CheckLibraryExists/CheckFunctionExists.cxx: In function 'int main(int, char**)':
+/tmp/instance-0/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CheckLibraryExists/CheckFunctionExists.cxx:17:25: error: too few arguments to function 'long long unsigned int __atomic_load_8(const volatile void*, int)'
+   CHECK_FUNCTION_EXISTS();
+                         ^
+
+whereas with a C compiler, we'll get:
+
+Building C object CMakeFiles/cmTC_4b0f4.dir/CheckFunctionExists.c.o
+/home/fabrice/buildroot/output/host/bin/riscv32-linux-gcc --sysroot=/home/fabrice/buildroot/output/host/riscv32-buildroot-linux-gnu/sysroot   -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -DCHECK_FUNCTION_EXISTS=__atomic_load_8  -DNDEBUG   -o CMakeFiles/cmTC_4b0f4.dir/CheckFunctionExists.c.o   -c /usr/share/cmake-3.16/Modules/CheckFunctionExists.c
+<command-line>: warning: conflicting types for built-in function ‘__atomic_load_8’ [-Wbuiltin-declaration-mismatch]
+/usr/share/cmake-3.16/Modules/CheckFunctionExists.c:7:3: note: in expansion of macro ‘CHECK_FUNCTION_EXISTS’
+   CHECK_FUNCTION_EXISTS(void);
+   ^~~~~~~~~~~~~~~~~~~~~
+Linking C executable cmTC_4b0f4
+/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTC_4b0f4.dir/link.txt --verbose=1
+/home/fabrice/buildroot/output/host/bin/riscv32-linux-gcc --sysroot=/home/fabrice/buildroot/output/host/riscv32-buildroot-linux-gnu/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -DCHECK_FUNCTION_EXISTS=__atomic_load_8  -DNDEBUG    CMakeFiles/cmTC_4b0f4.dir/CheckFunctionExists.c.o  -o cmTC_4b0f4  -latomic
+
+Fixes:
+ - http://autobuild.buildroot.org/results/2bf06c6a9e55b449ec5875cf9415a9e55b2065d6
+
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ CMakeLists.txt | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index edc73c5..0286647 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -9,7 +9,7 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
+ set(CMAKE_CXX_EXTENSIONS OFF)
+ 
+ project (pistache
+-    LANGUAGES CXX)
++    LANGUAGES C CXX)
+ 
+ include(GNUInstallDirs)
+ 
+-- 
+2.27.0
+