doc/manuals: support OSMO_GSM_MANUALS_DIR
Instead of only relying on pkg-config, support the environment variable
and fallback path like in other Osmocom repositories too. The same
script is used in other Osmocom repositories where manuals are built
without autotools.
Related: OS#4912
Change-Id: Iecfbfc2a7588c316642aa37be637cf3c02f76ac4
diff --git a/doc/manuals/Makefile b/doc/manuals/Makefile
index 1bd4b6e..d9a613d 100644
--- a/doc/manuals/Makefile
+++ b/doc/manuals/Makefile
@@ -1,4 +1,4 @@
-OSMO_GSM_MANUALS_DIR:=$(shell pkg-config osmo-gsm-manuals --variable=osmogsmmanualsdir)
+OSMO_GSM_MANUALS_DIR:=$(shell ./osmo-gsm-manuals-dir.sh)
sdcdir = .