contrib: bpg: include . before contrib

This avoids clashing with bpg's local libavutil.

contrib/src/bpg/pic.patch

@@ -5,7 +5,6 @@
  PWD:=$(shell pwd)
  
 -CFLAGS:=-Os -Wall -MMD -fno-asynchronous-unwind-tables -fdata-sections -ffunction-sections -fno-math-errno -fno-signed-zeros -fno-tree-vectorize -fomit-frame-pointer
-+CFLAGS+=-Os -Wall -MMD -fno-asynchronous-unwind-tables -fdata-sections -ffunction-sections -fno-math-errno -fno-signed-zeros -fno-tree-vectorize -fomit-frame-pointer
++CFLAGS:=-I. -Os -Wall -MMD -fno-asynchronous-unwind-tables -fdata-sections -ffunction-sections -fno-math-errno -fno-signed-zeros -fno-tree-vectorize -fomit-frame-pointer ${CFLAGS}
  CFLAGS+=-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_REENTRANT
- CFLAGS+=-I.
  CFLAGS+=-DCONFIG_BPG_VERSION=\"$(shell cat VERSION)\"