altos: Use --gc-sections

This allows the linker to discard unused functions.

Don't use -ffunctions-sections and -fdata-sections as that eliminates
several optimization opportunities and increases code size.

Signed-off-by: Keith Packard <[email protected]>

Author: keith-packard

src/Makefile.defs

@@ -23,6 +23,7 @@ OPT=-Os -Wl,-Map=$(PROGNAME)-$(VERSION).map
 
 PICOLIBC_CFLAGS= \
 	-specs=picolibc.specs \
+	-Wl,--gc-sections \
 	$(PICOLIBC_PRINTF_CFLAGS)
 
 AO_CFLAGS=\