many small fixes to allow user-overridable defaults

lib/compile_opts.sh

@@ -3,26 +3,49 @@
 # variables used externally
 # shellcheck disable=SC2034
 
+# default compile options
+
 # clean build directories before building
-CLEAN=true
+DEFAULT_CLEAN=true
 # enable link time optimization
-LTO=false
+DEFAULT_LTO=true
 # optimization level (0-3)
-OPT_LVL=0
+DEFAULT_OPT_LVL=3
 # static or shared build
-STATIC=true
+DEFAULT_STATIC=true
 # CPU type (amd64/v{1,2,3}...)
-CPU=native
+DEFAULT_CPU=native
 # architecture type
-ARCH=native
-# prefix to install, leave empty for non-system install (local)
-PREFIX=''
+DEFAULT_ARCH=native
+# prefix to install to, default is local install
+DEFAULT_PREFIX='local'
 # configure what ffmpeg enables
-FFMPEG_ENABLES=(
-	libopus
-	libdav1d
-	libsvtav1_psy
-	libaom
-	librav1e
-	libvmaf
+DEFAULT_FFMPEG_ENABLES="\
+libsvtav1_psy \
+libopus \
+libdav1d \
+libaom \
+librav1e \
+libvmaf \
+"
+
+# user-overridable compile option variable names
+FB_COMP_OPTS=(
+	CLEAN LTO OPT_LVL STATIC CPU ARCH PREFIX FFMPEG_ENABLES
 )
+
+# sets FB_COMP_OPTS to allow for user-overriding
+check_compile_opts_override() {
+	for opt in "${FB_COMP_OPTS[@]}"; do
+		declare -n defOptVal="DEFAULT_${opt}"
+		declare -n optVal="${opt}"
+		# use given value if not overridden
+		if [[ -n ${optVal} && ${optVal} != "${defOptVal}" ]]; then
+			echo_warn "setting given value for ${opt}=${optVal[*]}"
+			declare -g "${opt}=${optVal}"
+		else
+			echo_info "setting default value for ${opt}=${defOptVal[*]}"
+			declare -g "${opt}=${defOptVal}"
+		fi
+	done
+}