Adjust config.mk variables, fix cross-compilation, and don't run ldconfig.
--- a/Makefile
+++ b/Makefile
@@ -68,3 +68,6 @@
 $(GEN):
-	$(CC) -o $@ $(LDFLAGS) $@.o gen/util.o
+	$(BUILD_CC) -o $@ $(BUILD_LDFLAGS) $@.o gen/util.o
+
+gen/%.o:
+	$(BUILD_CC) -c -o $@ $(BUILD_CFLAGS) $(BUILD_CPPFLAGS) $<
 
@@ -84,3 +87,3 @@
 libgrapheme.so: $(SRC:=.o)
-	$(CC) -o $@ -shared $?
+	$(CC) -o $@ -shared $(LDFLAGS) $?
 
@@ -99,3 +102,2 @@
 	cp -f grapheme.h "$(DESTDIR)$(INCPREFIX)"
-	ldconfig || true
 
--- a/config.mk
+++ b/config.mk
@@ -13,8 +13,4 @@
 CPPFLAGS = -D_DEFAULT_SOURCE
-CFLAGS   = -std=c99 -Os -fPIC -Wall -Wextra -Wpedantic
-LDFLAGS  = -s
+CFLAGS  := -std=c99 -fPIC -Wall -Wextra -Wpedantic $(CFLAGS)
 
 # tools
-CC = cc
-AR = ar
-RANLIB = ranlib