CI: add a workaround for macOS builders on GHA

The GHA agents have installed capstone via brew.  Unfortunately, the
pkg-config data for the bottle provides an include path with an extra
component which we cannot reliably strip in the build system.  The
result is that `capstone/capstone.h` is not found.  Explicitly inject an
additional header search path from the command line to resolve the
header properly.

.github/workflows/build.yml

@@ -96,7 +96,7 @@ jobs:
         with:
           path: ${{ github.workspace }}/bloaty
       - name: configure
-        run: cmake -B build/bloaty -D CMAKE_BUILD_TYPE=Debug -D CMAKE_C_FLAGS=${{ matrix.cflags }} -D CMAKE_CXX_FLAGS=${{ matrix.cxxflags }} -G Ninja -S ${{ github.workspace }}/bloaty -D FILECHECK_EXECUTABLE=${{ github.workspace }}/build/llvm-project/bin/FileCheck -D YAML2OBJ_EXECUTABLE=${{ github.workspace }}/build/llvm-project/bin/yaml2obj -D LIT_EXECUTABLE=${{ github.workspace }}/llvm-project/llvm/utils/lit/lit.py
+        run: cmake -B build/bloaty -D CMAKE_BUILD_TYPE=Debug -D CMAKE_C_FLAGS=${{ matrix.cflags }} -D CMAKE_CXX_FLAGS=${{ matrix.cxxflags }} -G Ninja -S ${{ github.workspace }}/bloaty -D BLOATY_PREFER_SYSTEM_CAPSTONE=NO -D FILECHECK_EXECUTABLE=${{ github.workspace }}/build/llvm-project/bin/FileCheck -D YAML2OBJ_EXECUTABLE=${{ github.workspace }}/build/llvm-project/bin/yaml2obj -D LIT_EXECUTABLE=${{ github.workspace }}/llvm-project/llvm/utils/lit/lit.py
       - name: build
         run: cmake --build build/bloaty --config Debug
       - name: test

CMakeLists.txt

@@ -14,14 +14,17 @@ option(BLOATY_ENABLE_UBSAN "Enable undefined behavior sanitizer." OFF)
 option(BLOATY_ENABLE_CMAKETARGETS "Enable installing cmake target files." ON)
 option(BLOATY_ENABLE_BUILDID "Enable build id." ON)
 option(BLOATY_ENABLE_RE2 "Enable the support for regular expression functions." ON)
+option(BLOATY_PREFER_SYSTEM_CAPSTONE "Prefer to use the system capstone if available" YES)
 
 if(UNIX OR MINGW)
 find_package(PkgConfig)
 find_package(ZLIB)
 if(BLOATY_ENABLE_RE2)
   pkg_search_module(RE2 re2)
 endif()
-pkg_search_module(CAPSTONE capstone)
+if(BLOATY_PREFER_SYSTEM_CAPSTONE)
+  pkg_search_module(CAPSTONE capstone)
+endif()
 pkg_search_module(PROTOBUF protobuf)
 if(BLOATY_ENABLE_RE2)
   if(RE2_FOUND)