Index: Mk/Uses/replace.mk
===================================================================
--- /dev/null
+++ Mk/Uses/replace.mk
@@ -0,0 +1,66 @@
+# $FreeBSD$
+#
+# Replace %%PREFIX and %%LOCALBASE%% in sources
+#
+# Feature:	replace
+# Usage:	USES=replace
+#
+#   REPLACE_LOCALBASE_REGEX	a regular expression to match files to replace %%LOCALBASE%%
+#   REPLACE_LOCALBASE_FILES	list of files or glob pattern relative to ${WRKSRC}
+#   REPLACE_LOCALBASE_GLOB	list of glob pattern find(1) will match with
+#
+#   REPLACE_PREFIX_REGEX	a regular expression to match files to replace %%PREFIX%%
+#   REPLACE_PREFIX_FILES	list of files or glob pattern relative to ${WRKSRC}
+#   REPLACE_PREFIX_GLOB		list of glob pattern find(1) will match with
+#
+# To specify that ${WRKSRC}/path1/file and all .pl files in ${WRKSRC}/path2
+# should be processed:
+#
+#   REPLACE_PREFIX_FILES=	path1/file path2/*.pl
+#
+# MAINTAINER: portmgr@FreeBSD.org
+
+.if !defined(_INCLUDE_USES_REPLACE_MK)
+_INCLUDE_USES_REPLACE_MK=	yes
+
+_USES_patch+=	710:fix-localbase 711:fix-prefix
+
+fix-localbase:
+.if defined(REPLACE_LOCALBASE_REGEX)
+	@cd ${WRKSRC}; \
+		${FIND} -E . -type f -iregex '${REPLACE_LOCALBASE_REGEX}' \
+		-exec ${REINPLACE_CMD} -e 's|%%LOCALBASE%%|${LOCALBASE}|g' {} +
+.endif
+.if defined(REPLACE_LOCALBASE_GLOB)
+.  for f in ${REPLACE_LOCALBASE_GLOB}
+	@cd ${WRKSRC}; \
+		${FIND} . -type f -name '${f}' \
+		-exec ${REINPLACE_CMD} -e 's|%%LOCALBASE%%|${LOCALBASE}|g' {} +
+.  endfor
+.endif
+.if defined(REPLACE_LOCALBASE_FILES)
+	@cd ${WRKSRC}; \
+		${FIND} ${REPLACE_LOCALBASE_FILES} -type f \
+		-exec ${REINPLACE_CMD} -e 's|%%LOCALBASE%%|${LOCALBASE}|g' {} +
+.endif
+
+fix-prefix:
+.if defined(REPLACE_PREFIX_REGEX)
+	@cd ${WRKSRC}; \
+		${FIND} -E . -type f -iregex '${REPLACE_PREFIX_REGEX}' \
+		-exec ${REINPLACE_CMD} -e 's|%%PREFIX%%|${PREFIX}|g' {} +
+.endif
+.if defined(REPLACE_PREFIX_GLOB)
+.  for f in ${REPLACE_PREFIX_GLOB}
+	@cd ${WRKSRC}; \
+		${FIND} . -type f -name '${f}' \
+		-exec ${REINPLACE_CMD} -e 's|%%PREFIX%%|${PREFIX}|g' {} +
+.  endfor
+.endif
+.if defined(REPLACE_PREFIX_FILES)
+	@cd ${WRKSRC}; \
+		${FIND} ${REPLACE_PREFIX_FILES} -type f \
+		-exec ${REINPLACE_CMD} -e 's|%%PREFIX%%|${PREFIX}|g' {} +
+.endif
+
+.endif
Index: graphics/acidwarp-sdl/Makefile
===================================================================
--- graphics/acidwarp-sdl/Makefile
+++ graphics/acidwarp-sdl/Makefile
@@ -9,7 +9,7 @@
 
 BUILD_DEPENDS=	convert:graphics/ImageMagick7
 
-USES=		cmake sdl
+USES=		cmake replace sdl
 USE_SDL=	sdl2
 
 USE_GITHUB=	yes
@@ -17,6 +17,8 @@
 GH_PROJECT=	acidwarp
 GH_TAGNAME=	698c4e1
 
+REPLACE_PREFIX_FILES=	acidwarp.desktop
+
 # Fix build on recent current (clang11)
 CFLAGS+=	-fcommon
 
@@ -26,9 +28,6 @@
 		share/applications/acidwarp.desktop \
 		share/pixmaps/acidwarp.png
 
-post-patch:
-	${REINPLACE_CMD} -e 's|%%PREFIX%%|${PREFIX}|g' ${WRKSRC}/acidwarp.desktop
-
 do-install:
 	${STRIP_CMD} ${WRKSRC}/bin/acidwarp
 	${INSTALL_PROGRAM} ${WRKSRC}/bin/acidwarp ${STAGEDIR}${PREFIX}/bin