remove rpavlik-cmake-modules submodule and dead cotire references

Only EnableExtraCompilerWarnings.cmake was ever used from the ~150-file
rpavlik submodule; vendor it into cmake/ and drop the submodule. Also
remove the dead cotire module-path entry and the vestigial ENABLE_COTIRE
option (cotire is never invoked and its directory no longer exists).
Repoint the submodule-initialized check at libRocket.

Follow-up to #7646.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: Goober5000

.gitmodules

@@ -1,6 +1,3 @@
-[submodule "cmake/external/rpavlik-cmake-modules"]
-	path = cmake/external/rpavlik-cmake-modules
-	url = https://github.com/rpavlik/cmake-modules.git
 [submodule "lib/libRocket"]
 	path = lib/libRocket
 	url = https://github.com/scp-fs2open/libRocket.git

CMakeLists.txt

@@ -48,14 +48,12 @@ endif()
 PROJECT(FS2_Open LANGUAGES ${FSO_LANGUAGES})
 
 # Check if the external modules exists
-IF(NOT IS_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/cmake/external/rpavlik-cmake-modules/launcher-templates")
+IF(NOT IS_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/lib/libRocket/Build")
 	message(FATAL_ERROR "External submodules could not be found. Please make sure you have updated your submodules.")
 endif()
 
 LIST(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
 LIST(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/finder")
-LIST(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/external/rpavlik-cmake-modules")
-LIST(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/external/cotire")
 
 # this must be set before include(toolchain)
 if(WIN32 AND CMAKE_SIZEOF_VOID_P EQUAL 4)
@@ -122,8 +120,6 @@ SET(FSO_RUN_ARGUMENTS "" CACHE STRING "Additional arguments passed to a generate
 
 option(FSO_INSTALL_DEBUG_FILES "Install some debug files (currently only PDB files on windows)" OFF)
 
-option(ENABLE_COTIRE "Enable cotire for faster compilation. Enabled by default." ON)
-
 option(FSO_RELEASE_LOGGING "Enable logging output for release builds" OFF)
 
 OPTION(FSO_BUILD_WITH_FFMPEG "Enable the usage of FFmpeg for sound and custscenes" ON)
@@ -172,7 +168,6 @@ MARK_AS_ADVANCED(FORCE FSO_USE_LUAJIT)
 MARK_AS_ADVANCED(FORCE FSO_DEVELOPMENT_MODE)
 MARK_AS_ADVANCED(FORCE FSO_FATAL_WARNINGS)
 mark_as_advanced(FORCE FSO_INSTALL_DEBUG_FILES)
-mark_as_advanced(FORCE ENABLE_COTIRE)
 mark_as_advanced(FORCE FSO_RELEASE_LOGGING)
 mark_as_advanced(FORCE FSO_BUILD_WITH_FFMPEG)
 mark_as_advanced(FORCE FSO_BUILD_WITH_DISCORD)

cmake/EnableExtraCompilerWarnings.cmake

@@ -0,0 +1,88 @@
+# - Add flags to compile with extra warnings
+#
+#  enable_extra_compiler_warnings(<targetname>)
+#  globally_enable_extra_compiler_warnings() - to modify CMAKE_CXX_FLAGS, etc
+#    to change for all targets declared after the command, instead of per-command
+#
+#
+# Original Author:
+# 2010 Ryan Pavlik <rpavlik@iastate.edu> <abiryan@ryand.net>
+# http://academic.cleardefinition.com
+# Iowa State University HCI Graduate Program/VRAC
+#
+# Copyright Iowa State University 2009-2010.
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+if(__enable_extra_compiler_warnings)
+	return()
+endif()
+set(__enable_extra_compiler_warnings YES)
+
+macro(_enable_extra_compiler_warnings_flags)
+	set(_flags)
+	if(MSVC)
+		option(COMPILER_WARNINGS_EXTREME
+			"Use compiler warnings that are probably overkill."
+			off)
+		mark_as_advanced(COMPILER_WARNINGS_EXTREME)
+		set(_flags "/W4")
+		if(COMPILER_WARNINGS_EXTREME)
+			set(_flags "${_flags} /Wall /wd4619 /wd4668 /wd4820 /wd4571 /wd4710")
+		endif()
+	else()
+		include(CheckCXXCompilerFlag)
+		set(_flags)
+
+		check_cxx_compiler_flag(-W SUPPORTS_W_FLAG)
+		if(SUPPORTS_W_FLAG)
+			set(_flags "${_flags} -W")
+		endif()
+
+		check_cxx_compiler_flag(-Wall SUPPORTS_WALL_FLAG)
+		if(SUPPORTS_WALL_FLAG)
+			set(_flags "${_flags} -Wall")
+		endif()
+
+		check_cxx_compiler_flag(-Wextra SUPPORTS_WEXTRA_FLAG)
+		if(SUPPORTS_WEXTRA_FLAG)
+			set(_flags "${_flags} -Wextra")
+		endif()
+
+		if(SUPPORTS_WALL_FLAG)
+			# At least GCC includes -Wmaybe-uninitialized in -Wall, which
+			# unneccesarily whines about boost::optional (by it's nature
+			# it's a "maybe" warning - prone to noisy false-positives)
+			check_cxx_compiler_flag(-Wno-maybe-uninitialized SUPPORTS_WNO_MAYBE_UNINITIALIZED_FLAG)
+			if(SUPPORTS_WNO_MAYBE_UNINITIALIZED_FLAG)
+				set(_flags "${_flags} -Wno-maybe-uninitialized")
+			endif()
+		endif()
+	endif()
+endmacro()
+
+function(enable_extra_compiler_warnings _target)
+	_enable_extra_compiler_warnings_flags()
+	get_target_property(_origflags ${_target} COMPILE_FLAGS)
+	if(_origflags)
+		set_property(TARGET
+			${_target}
+			PROPERTY
+			COMPILE_FLAGS
+			"${_flags} ${_origflags}")
+	else()
+		set_property(TARGET
+			${_target}
+			PROPERTY
+			COMPILE_FLAGS
+			"${_flags}")
+	endif()
+
+endfunction()
+
+function(globally_enable_extra_compiler_warnings)
+	_enable_extra_compiler_warnings_flags()
+	set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${_flags}" PARENT_SCOPE)
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_flags}" PARENT_SCOPE)
+endfunction()