[RFC] make: split global linker and compile flags

Future emscripten versions warn if link-only options
are set during compilation.

RFC: Alternatively, do not set LDFLAGS globally only at the final step
     as this is the only instance of linking (currently at least).

Author: TheOneric

Makefile

@@ -4,7 +4,9 @@
 BASE_DIR:=$(dir $(realpath $(firstword $(MAKEFILE_LIST))))
 DIST_DIR:=$(BASE_DIR)dist/libraries
 
-GLOBAL_CFLAGS:=-O3 -s ENVIRONMENT=web,webview
+GLOBAL_CFLAGS:=-O3
+GLOBAL_LDFLAGS:=-s ENVIRONMENT=web,webview
+export LDFLAGS = $(GLOBAL_LDFLAGS)
 
 all: subtitleoctopus
 
@@ -158,7 +160,6 @@ $(DIST_DIR)/lib/libharfbuzz.a: build/lib/freetype/build_hb/dist_hb/lib/libfreety
 		-s NO_EXIT_RUNTIME=1 \
 		-s MODULARIZE=1 \
 		" \
-		LDFLAGS="" \
 		--prefix="$(DIST_DIR)" \
 		--host=x86-none-linux \
 		--build=x86_64 \