One build directory for every cmake flag combination

This will increase disk space usage. There is also no auto cleanup.
But it allows to have multiple servers with multiple different
cmake flags using the same source git repo.
Without deleting the build directory on every rebuild or using
the wrong flags.

Author: ChillerDragon

lib/include/update/cmake.sh

@@ -1,5 +1,16 @@
 #!/bin/bash
 
+# prints the folder name of the cmake build directory
+# the format is always the following:
+#
+#  build-[sha256sum of cmake flags]
+#
+get_cmake_build_dir() {
+	local sum
+	sum="$(printf '%s' "${CFG_CMAKE_FLAGS[*]}" | sha256sum | cut -d' ' -f1)"
+	printf 'build-%s' "$sum"
+}
+
 function cmake_refresh_teeworlds_binary() {
 	if [ ! -f "$CFG_GIT_PATH_MOD/build/$CFG_COMPILED_BIN" ]
 	then
@@ -19,24 +30,25 @@ function cmake_refresh_teeworlds_binary() {
 	if [ "$CFG_GITPATH_ANTIBOT" != "" ]
 	then
 		log "refreshing antibot binary ..."
+		local build_dir="$(get_cmake_build_dir)"
 
 		if [ -f "$CFG_GITPATH_ANTIBOT"/libantibot.so ] && \
-			[ -f "$CFG_GITPATH_ANTIBOT"/build/libantibot.so ]
+			[ -f "$CFG_GITPATH_ANTIBOT"/"$build_dir"/libantibot.so ]
 		then
 			err "Error: found libantibot.so in root and build dir of $CFG_GITPATH_ANTIBOT"
 			err "       this is ambiguous. Please delete one of the files"
 			err ""
 			err "        $CFG_GITPATH_ANTIBOT/libantibot.so"
-			err "        $CFG_GITPATH_ANTIBOT/build/libantibot.so"
+			err "        $CFG_GITPATH_ANTIBOT/$build_dir/libantibot.so"
 			err ""
 			exit 1
 		fi
 
 		local libantibot_path=''
 		for libantibot_path_candidate in \
 			"$CFG_GITPATH_ANTIBOT"/libantibot.so \
-			"$CFG_GITPATH_ANTIBOT"/build/libantibot.so \
-			"$CFG_GIT_PATH_MOD"/build/libantibot.so
+			"$CFG_GITPATH_ANTIBOT"/"$build_dir"/libantibot.so \
+			"$CFG_GIT_PATH_MOD"/"$build_dir"/libantibot.so
 		do
 			if [ -f "$libantibot_path_candidate" ]
 			then
@@ -180,6 +192,7 @@ function cmake_update() {
 	update_antibot
 	apply_git_patches
 	bin_commit="$(git rev-parse HEAD)"
+	local build_dir="$(get_cmake_build_dir)"
 	mkdir -p "$SCRIPT_ROOT/lib/tmp"
 	local cmake_cache="$SCRIPT_ROOT/lib/tmp/cmake_flags.txt"
 	if [ -f "$cmake_cache" ]
@@ -189,16 +202,17 @@ function cmake_update() {
 			log "cmake flags changed:"
 			log " old='$(cat "$cmake_cache")'"
 			log " new='${arg_cmake_flags[*]}'"
-			log "deleting build directory ..."
-			rm -rf build
+			log "you might want to cleanup the now potentially old unused build dir in $PWD"
+			# log "deleting build directory ..."
+			# rm -rf "$build_dir"
 		fi
 	fi
 
 	register_hook_before_compile
 
 	echo "${arg_cmake_flags[*]}" > "$cmake_cache"
-	mkdir -p build || { err "Error: creating dir build/"; exit 1; }
-	cd build || { err "Could not enter build/ directory"; exit 1; }
+	mkdir -p "$build_dir" || { err "Error: creating dir $build_dir"; exit 1; }
+	cd "$build_dir" || { err "Could not enter $build_dir directory"; exit 1; }
 	branch="$(git branch | sed -n '/\* /s///p')"
 
 	local build_fail=0