Replace CCFLAGS with description of how to add flags to HOSTCC.
diff --git a/configure b/configure
index 4e05af7..bf2561b 100644
--- a/configure
+++ b/configure
@@ -4,10 +4,13 @@
# A synonym.
[ -z "$CROSS_COMPILE" ] && CROSS_COMPILE="$CROSS"
-
[ -z "$CFLAGS" ] && CFLAGS="-Wall -Wundef -Wno-char-subscripts"
+# Required for our expected ABI. we're 8-bit clean thus "char" must be unsigned.
CFLAGS="$CFLAGS -funsigned-char"
+
[ -z "$OPTIMIZE" ] && OPTIMIZE="-Os -ffunction-sections -fdata-sections -Wl,--gc-sections"
[ -z "$CC" ] && CC=cc
[ -z "$STRIP" ] && STRIP=strip
+
+# If HOSTCC needs CFLAGS, add them to the variable ala HOSTCC="blah-cc --static"
[ -z "$HOSTCC" ] && HOSTCC=gcc