Add a toolchain and logic for building 32-bit Linux libraries

Adds a toolchain file that defines what is needed to build the libraries on Linux for a 32-bit, i386, architecture, and move existing toolchain files, into a subfolder.  Adds special logic for libsecret, which always tries to include glib for x86_64 if it is present, instead of i386.

PiperOrigin-RevId: 291193156

Author: a-maurice

README.md

@@ -190,14 +190,14 @@ Currently, the third party libraries that can be provided this way are:
 
 #### Building with CMake for iOS
 The Firebase C++ SDK comes with a CMake config file to build the library for
-iOS platforms, [cmake/ios.cmake](/cmake/ios.cmake).  In order to build with it,
-when running the CMake configuration pass it in with the CMAKE_TOOLCHAIN_FILE
-definition.  For example, to build the Analytics library for iOS, you could run
-the following commands:
+iOS platforms, [cmake/toolchains/ios.cmake](/cmake/toolchains/ios.cmake).  In
+order to build with it, when running the CMake configuration pass it in with
+the CMAKE_TOOLCHAIN_FILE definition.  For example, to build the Analytics
+library for iOS, you could run the following commands:
 
 ``` bash
 mkdir ios_build && cd ios_build
-cmake -DCMAKE_TOOLCHAIN_FILE=../cmake/ios.cmake ..
+cmake -DCMAKE_TOOLCHAIN_FILE=../cmake/toolchains/ios.cmake ..
 cmake --build . --target firebase_analytics
 ```
 

app/CMakeLists.txt

@@ -191,6 +191,11 @@ else()
                            systems via: \
                            apt-get install libsecret-1-dev")
     endif()
+    # If building for 32 bit, the include directories might need to be fixed.
+    if("${CMAKE_CXX_FLAGS}" MATCHES "-m32")
+      string(REGEX REPLACE "x86_64" "i386"
+             LIBSECRET_INCLUDE_DIRS "${LIBSECRET_INCLUDE_DIRS}")
+    endif()
     set(app_desktop_extra_SRCS
         src/secure/user_secure_linux_internal.cc
         src/locale.cc

cmake/cpp_pack.cmake

@@ -46,7 +46,13 @@ if(${FIREBASE_CPP_BUILD_PACKAGE})
   elseif(APPLE)
     set(FIREBASE_LIB_CONFIG_PATH "darwin")
   else()
-    set(FIREBASE_LIB_CONFIG_PATH "linux")
+    # Check if building for 32 bit
+    message(STATUS "CMAKE_CXX_FLAGS: ${CMAKE_CXX_FLAGS}")
+    if("${CMAKE_CXX_FLAGS}" MATCHES "-m32")
+      set(FIREBASE_LIB_CONFIG_PATH "linux/i386")
+    else()
+      set(FIREBASE_LIB_CONFIG_PATH "linux/x86_64")
+    endif()
   endif()
 endif()
 

cmake/ios.cmake renamed to cmake/toolchains/ios.cmake

@@ -0,0 +1,5 @@
+# Toolchain file for building 32-bit Linux libraries
+
+set(CMAKE_C_FLAGS -m32)
+set(CMAKE_CXX_FLAGS -m32)
+set(CMAKE_LIBRARY_PATH "/usr/lib/i386-linux-gnu")

cmake/ios_simulator.cmake renamed to cmake/toolchains/ios_simulator.cmake

@@ -27,7 +27,7 @@ cd mac_ios_build
 
 # Configure cmake with tests enabled
 # and disable use of libsecret due to not working on kokoro builders
-cmake -DCMAKE_TOOLCHAIN_FILE=../cmake/ios.cmake .. -DFIREBASE_CPP_BUILD_TESTS=ON -DFIREBASE_FORCE_FAKE_SECURE_STORAGE=ON
+cmake -DCMAKE_TOOLCHAIN_FILE=../cmake/toolchains/ios.cmake .. -DFIREBASE_CPP_BUILD_TESTS=ON -DFIREBASE_FORCE_FAKE_SECURE_STORAGE=ON
 
 # Build the SDK and the tests
 cmake --build .