unify the linker GC flags to be used everywhere

We enabled theses flags in most directs more or less directly but with varying inconsistencies.

For example native does not have it, but native-tft have it.

This makes the native linux build go from 86M to 43M.

Author: Jorropo

platformio.ini

@@ -22,8 +22,8 @@ extra_scripts =
 ; of code is a heap corruption bug!
 ; FIXME: fix lib/BluetoothOTA dependency back on src/ so we can remove -Isrc
 ; The Radiolib stuff will speed up building considerably. Exclud all the stuff we dont need.
-build_flags = -Wno-missing-field-initializers
-
+build_flags =
+	-Wno-missing-field-initializers
 	-Wno-format
 	-Isrc -Isrc/mesh -Isrc/mesh/generated -Isrc/gps -Isrc/buzz -Wl,-Map,"${platformio.build_dir}"/output.map
 	-DUSE_THREAD_NAMES
@@ -59,6 +59,10 @@ build_flags = -Wno-missing-field-initializers
 	#-D OLED_PL=1
 	#-D DEBUG_HEAP=1 ; uncomment to add free heap space / memory leak debugging logs
 	#-D DEBUG_LOOP_TIMING=1 ; uncomment to add main loop timing logs
+	-ffunction-sections
+	-fdata-sections
+	-Wl,--gc-sections
+	-Wl,--as-needed
 
 monitor_speed = 115200
 monitor_filters = direct

variants/native/portduino/platformio.ini

@@ -27,7 +27,7 @@ build_type = release
 lib_deps =
   ${native_base.lib_deps}
   ${device-ui_base.lib_deps}
-build_flags = ${native_base.build_flags} -Os -lX11 -linput -lxkbcommon -ffunction-sections -fdata-sections -Wl,--gc-sections
+build_flags = ${native_base.build_flags} -Os -lX11 -linput -lxkbcommon
   -D RAM_SIZE=16384
   -D USE_X11=1
   -D HAS_TFT=1
@@ -55,7 +55,7 @@ build_type = release
 lib_deps =
   ${native_base.lib_deps}
   ${device-ui_base.lib_deps}
-build_flags = ${native_base.build_flags} -Os -ffunction-sections -fdata-sections -Wl,--gc-sections
+build_flags = ${native_base.build_flags} -Os
   -D RAM_SIZE=8192
   -D USE_FRAMEBUFFER=1
   -D LV_COLOR_DEPTH=32

variants/stm32/stm32.ini

@@ -30,8 +30,6 @@ build_flags =
   -DPIO_FRAMEWORK_ARDUINO_NANOLIB_FLOAT_PRINTF ; This is REQUIRED for at least traceroute debug prints - without it the length ends up uninitialized.
   -DDEBUG_MUTE ; You can #undef DEBUG_MUTE in certain source files if you need the logs.
   -fmerge-all-constants
-  -ffunction-sections
-  -fdata-sections
   -DRADIOLIB_EXCLUDE_SX128X=1
   -DRADIOLIB_EXCLUDE_SX127X=1
   -DRADIOLIB_EXCLUDE_LR11X0=1