From: Gregor Jasny <gjasny@googlemail.com>
Date: Fri, 2 Jun 2023 10:34:56 +0000 (+0200)
Subject: Fix Intel Xcode builds with assembly
X-Git-Tag: v1.5.6^2~142^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7e09f07b325b6e2a95e11776f23ff97716b7b924;p=thirdparty%2Fzstd.git

Fix Intel Xcode builds with assembly

When forcing the source file language to `C`, Xcode enforces
the file to be compiled as `C` by appending `-x c` to the
compiler command line.

For now try to limit the damage and only enforce the language
if the ASM and C compilers differ.

Reproducer (CMake `3.26.4`, Xcode `14.3`):
```
cmake -S build/cmake -B _b -GXcode -DCMAKE_OSX_ARCHITECTURES=x86_64
cmake --build _b
```

Fix: #3622
---

diff --git a/build/cmake/lib/CMakeLists.txt b/build/cmake/lib/CMakeLists.txt
index 457b54797..3cab017a7 100644
--- a/build/cmake/lib/CMakeLists.txt
+++ b/build/cmake/lib/CMakeLists.txt
@@ -105,7 +105,9 @@ endif ()
 # Our assembly expects to be compiled by a C compiler, and is only enabled for
 # __GNUC__ compatible compilers. Otherwise all the ASM code is disabled by
 # macros.
-set_source_files_properties(${Sources} PROPERTIES LANGUAGE C)
+if(NOT CMAKE_ASM_COMPILER STREQUAL CMAKE_C_COMPILER)
+    set_source_files_properties(${Sources} PROPERTIES LANGUAGE C)
+endif()
 
 macro (add_definition target var)
     if (NOT ("${${var}}" STREQUAL ""))