update CML to install to /usr/local on macos

Author: mattkjames7

.github/workflows/ci.yml

@@ -93,7 +93,7 @@ jobs:
 
       - name: Build mgconsole
         run: |
-          cmake -B build -G Ninja -DOPENSSL_ROOT_DIR="$(brew --prefix openssl)" -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local .
+          cmake -B build -G Ninja -DOPENSSL_ROOT_DIR="$(brew --prefix openssl)" -DCMAKE_BUILD_TYPE=Release .
           cmake --build build
           sudo cmake --install build
 

CMakeLists.txt

@@ -33,11 +33,16 @@ string(TOLOWER "${CMAKE_BUILD_TYPE}" CMAKE_BUILD_TYPE_LOWERCASE)
 # Enable explicit static linking of SSL because of generic Linux binary.
 set(MGCONSOLE_STATIC_SSL OFF CACHE STRING "Statically link SSL")
 
-# Set default installation directory to '/usr'
+# Set default installation directory
 if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
-    # '/usr' is a special case, for more details see:
-    # https://cmake.org/cmake/help/latest/module/GNUInstallDirs.html#special-cases
-    set(CMAKE_INSTALL_PREFIX "/usr" CACHE PATH "install dir" FORCE)
+    if(APPLE)
+        # On macOS, use /usr/local as /usr/bin is protected by SIP
+        set(CMAKE_INSTALL_PREFIX "/usr/local" CACHE PATH "install dir" FORCE)
+    else()
+        # '/usr' is a special case, for more details see:
+        # https://cmake.org/cmake/help/latest/module/GNUInstallDirs.html#special-cases
+        set(CMAKE_INSTALL_PREFIX "/usr" CACHE PATH "install dir" FORCE)
+    endif()
 endif()
 
 add_subdirectory(src)