Fix dependencies

Signed-off-by: Sebastian Ramacher <sebastian+dev@ramacher.at>

doc/Makefile

@@ -6,7 +6,7 @@ include ../colors.mk
 include config.mk
 
 MAN_SOURCES=$(wildcard man/*.rst) $(wildcard man/*.txt) man/conf.py
-DOXYGEN_SOURCES=$(wildcard ../*.h) Doxyfile
+DOXYGEN_SOURCES=$(wildcard ../zathura/*.h) Doxyfile
 HTML_SOURCES=$(wildcard *.rst api/*.rst configuration/*.rst installation/*.rst usage/*.rst) conf.py
 
 SPHINX_OPTS+=-d $(SPHINX_BUILDDIR)/doctrees