tcsh: fix memory issue on musl

srcpkgs/tcsh/template

@@ -1,7 +1,7 @@
 # Template file for 'tcsh'
 pkgname=tcsh
 version=6.20.00
-revision=1
+revision=2
 build_style=gnu-configure
 register_shell="/bin/tcsh /bin/csh"
 conf_files="/etc/csh.login /etc/csh.cshrc"
@@ -16,6 +16,13 @@ checksum=b89de7064ab54dac454a266cfe5d8bf66940cb5ed048d0c30674ea62e7ecef9d
 post_extract() {
 	sed -i '/define BSDWAIT/d' sh.proc.c
 }
+pre_configure() {
+case "$XBPS_TARGET_MACHINE" in
+	*-musl)
+		sed -e ';s/# undef SYSMALLOC/# define SYSMALLOC/g' -i config_f.h
+	;;
+esac
+}
 pre_build() {
 	make CC_FOR_GETHOST="${BUILD_CC}" CFLAGS="${BUILD_CFLAGS}" gethost
 }