GNUmakefile.mjo: allow SRCS to be prepopulated

We don't want to kpsewhich everything. Often, there are additional
fixed files that should go in SRCS, and that don't need to be found at
build time. By using "+=" the first time we modify SRCS, we make it
possible for consumers to supply their own SRCS.

diff --git a/GNUmakefile.mjo b/GNUmakefile.mjo
index 72fbb03ad0a3c72a5fe1a7c8c837405b1bc0fad0..3aaf3237c86d3be096246c518f5b971e11502892 100644 (file)
--- a/GNUmakefile.mjo
+++ b/GNUmakefile.mjo
@@ -66,7 +66,11 @@ endif
 # Use kpsewhich (from the kpathsea suite) to find the absolute paths
 # of the bibtex/mjotex files listed in in $(BIBS)/$(MJOTEX). The SRCS
 # variable should contain all (Bib)TeX source files for the document.
-SRCS = $(PN).tex
+# We append to $(SRCS) here, even though it will typically be empty,
+# to allow projects to pre-populate it. (In many cases, there will
+# be extra tikz images or whatever that qualify as source files,
+# should trigger a rebuild, and do not need to be kpsewhich'd).
+SRCS += $(PN).tex
 ifdef BIBS
 BIBPATHS = $(shell kpsewhich $(BIBS))
 SRCS += $(BIBPATHS)