build/Makefile.common: full path for shrink script

Use the full path to shrink-pdfs.sh, so it works as expected when the
symlinks are not present. This is how pysim uses the publish/shrink
targets.

Fix for:
  build/shrink-pdfs.sh _build/latex/osmopysim-usermanual.pdf
  make: build/shrink-pdfs.sh: Command not found

Related: SYS#6380
Change-Id: Iba6e0e4932741adcb9e54e54eb7774716fb2e244
---
M build/Makefile.common.inc
1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/build/Makefile.common.inc b/build/Makefile.common.inc
index 9e79621..80f2c19 100644
--- a/build/Makefile.common.inc
+++ b/build/Makefile.common.inc
@@ -24,7 +24,7 @@
 # Reduce pdf size by storing the embedded images with less quality (SYS#6380)
 shrink: $(SHRINK_MARKER)
 $(SHRINK_MARKER): $(UPLOAD_FILES)
-	build/shrink-pdfs.sh $(UPLOAD_FILES)
+	$(OSMO_GSM_MANUALS_DIR)/build/shrink-pdfs.sh $(UPLOAD_FILES)
 
 # Publish to $UPLOAD_PATH
 upload: shrink

