autotools: link with gcc instead of g++ when targeting windows, too

we used to link with mingw-g++ because that's what harfbuzz Makefile.am
does. I don't know why they do that. I don't know what their cmake'ry or
meson'ry do, either. But this does seem to work and eliminates linkage
to libgcc_s.

Reference issue: #457.

Author: sezero

Makefile.am

@@ -121,7 +121,7 @@ if USE_BUILTIN_HARFBUZZ
 LOCAL_HB_FLAGS = -I$(srcdir)/$(HARFBUZZ_PATH) -I$(srcdir)/$(HARFBUZZ_PATH)/src -DHAVE_CONFIG_H -DFT_CONFIG_OPTION_USE_HARFBUZZ
 LOCAL_HB_SOURCES = $(HARFBUZZ_SOURCES)
 if OS_WIN32
-LINKER = $(CXXLINK)
+LINKER = $(LINK) #$(CXXLINK)
 else
 LINKER = $(LINK)
 endif

Makefile.in

@@ -831,7 +831,7 @@ HARFBUZZ_SOURCES = \
 @USE_BUILTIN_HARFBUZZ_TRUE@LOCAL_HB_FLAGS = -I$(srcdir)/$(HARFBUZZ_PATH) -I$(srcdir)/$(HARFBUZZ_PATH)/src -DHAVE_CONFIG_H -DFT_CONFIG_OPTION_USE_HARFBUZZ
 @USE_BUILTIN_HARFBUZZ_TRUE@LOCAL_HB_SOURCES = $(HARFBUZZ_SOURCES)
 @OS_WIN32_FALSE@@USE_BUILTIN_HARFBUZZ_TRUE@LINKER = $(LINK)
-@OS_WIN32_TRUE@@USE_BUILTIN_HARFBUZZ_TRUE@LINKER = $(CXXLINK)
+@OS_WIN32_TRUE@@USE_BUILTIN_HARFBUZZ_TRUE@LINKER = $(LINK) #$(CXXLINK)
 @USE_BUILTIN_HARFBUZZ_FALSE@LINKER = $(LINK)
 libSDL2_ttf_la_LDFLAGS = \
 	-no-undefined		\

ltmain.sh

@@ -4785,7 +4785,7 @@ func_mode_link ()
       # -p, -pg, --coverage, -fprofile-* pass through profiling flag for GCC
       # @file GCC response files
       -64|-mips[0-9]|-r[0-9][0-9]*|-xarch=*|-xtarget=*|+DA*|+DD*|-q*|-m*| \
-      -t[45]*|-txscale*|-p|-pg|--coverage|-fprofile-*|-F*|@*)
+      -t[45]*|-txscale*|-p|-pg|--coverage|-fprofile-*|-F*|-static-*|@*)
         func_quote_for_eval "$arg"
 	arg="$func_quote_for_eval_result"
         func_append compile_command " $arg"