CMake fix for 32-bit x86

Author: scivision

CMakeLists.txt

@@ -17,14 +17,21 @@ add_library("${PROJECT_NAME}")
 set(OPENLIBM_ARCH_FOLDER ${CMAKE_SYSTEM_PROCESSOR})
 string(TOLOWER "${OPENLIBM_ARCH_FOLDER}" OPENLIBM_ARCH_FOLDER)
 
-if(OPENLIBM_ARCH_FOLDER STREQUAL "amd64" OR OPENLIBM_ARCH_FOLDER STREQUAL "x86_64")
-    set(OPENLIBM_ARCH_FOLDER "amd64")
+# CMAKE_SYSTEM_PROCESSOR reflects the host instead of the selected MinGW target.
+# Use pointer size to disambiguate x86/x64.
+if(OPENLIBM_ARCH_FOLDER STREQUAL "x86_64" OR OPENLIBM_ARCH_FOLDER STREQUAL "amd64" OR
+   OPENLIBM_ARCH_FOLDER STREQUAL "x86" OR OPENLIBM_ARCH_FOLDER STREQUAL "i686")
+    if(CMAKE_SIZEOF_VOID_P EQUAL 8)
+        set(OPENLIBM_ARCH_FOLDER "amd64")
+    elseif(CMAKE_SIZEOF_VOID_P EQUAL 4)
+        set(OPENLIBM_ARCH_FOLDER "i387")
+    else()
+        message(FATAL_ERROR "Unsupported pointer size: ${CMAKE_SIZEOF_VOID_P}")
+    endif()
 elseif(OPENLIBM_ARCH_FOLDER STREQUAL "arm64" OR OPENLIBM_ARCH_FOLDER STREQUAL "aarch64")
     set(OPENLIBM_ARCH_FOLDER "aarch64")
 elseif(OPENLIBM_ARCH_FOLDER STREQUAL "armv7-a")
     set(OPENLIBM_ARCH_FOLDER "arm")
-elseif(OPENLIBM_ARCH_FOLDER STREQUAL "x86" OR OPENLIBM_ARCH_FOLDER STREQUAL "i686")
-    set(OPENLIBM_ARCH_FOLDER "i387")
 elseif(OPENLIBM_ARCH_FOLDER STREQUAL "powerpc")
     set(OPENLIBM_ARCH_FOLDER "powerpc")
 elseif(OPENLIBM_ARCH_FOLDER STREQUAL "riscv64")