use full path on command line when compiling,

so that gdb shows full path in stack traces.

R=r
DELTA=4  (4 added, 0 deleted, 0 changed)
OCL=32522
CL=32528

src/Make.conf

@@ -11,3 +11,7 @@ YFLAGS=-d
 ifndef GOBIN
 GOBIN=$(HOME)/bin
 endif
+PWD=$(shell pwd)
+
+%.$O: %.c
+	$(CC) $(CFLAGS) -c $(PWD)/$*.c