Index: /trunk/psModules/Makefile.am
===================================================================
--- /trunk/psModules/Makefile.am	(revision 5365)
+++ /trunk/psModules/Makefile.am	(revision 5366)
@@ -8,6 +8,8 @@
 EXTRA_DIST = Doxyfile.in psmodule-config.in psmodule.pc.in
 
+if DOXYGEN
+
 docs: Doxyfile $(prefix)/docs/psmodule $(mandir)/man3
-	$(DOXYGEN)
+	doxygen Doxyfile
 	mv -f $(prefix)/docs/psmodule/man/man3/* $(mandir)/man3
 	rm -rf $(prefix)/docs/psmodule/man
@@ -24,3 +26,5 @@
 CLEANFILES = $(prefix)/docs/psmodule/*
 
+endif
+
 test: check
Index: /trunk/psModules/configure.ac
===================================================================
--- /trunk/psModules/configure.ac	(revision 5365)
+++ /trunk/psModules/configure.ac	(revision 5366)
@@ -47,14 +47,6 @@
 dnl doxygen -------------------------------------------------------------------
 
-AC_PATH_PROG([DOXYGEN], [doxygen], [missing])
-if test "$DOXYGEN" = "missing" ; then
-  AC_MSG_ERROR([doxygen is required])
-fi
-
-dnl needed by doxygen
-AC_PATH_PROG([PERL], [perl], [missing])
-if test "$PERL" = "missing" ; then
-  AC_MSG_ERROR([perl is required])
-fi
+AC_CHECK_PROG([doxygen], [doxygen], [true], [false])
+AM_CONDITIONAL(DOXYGEN, test x$doxygen = xtrue)
 
 dnl pslib ---------------------------------------------------------------------
Index: /trunk/psModules/test/imsubtract/Makefile.am
===================================================================
--- /trunk/psModules/test/imsubtract/Makefile.am	(revision 5365)
+++ /trunk/psModules/test/imsubtract/Makefile.am	(revision 5366)
@@ -11,6 +11,6 @@
 
 tst_pmImageSubtract_SOURCES = tst_pmImageSubtract.c
-tst_pmSubstractBias_SOURCES = tst_pmSubstractBias.c
-tst_pmSubstractSky_SOURCES = tst_pmSubstractSky.c
+tst_pmSubtractBias_SOURCES = tst_pmSubtractBias.c
+tst_pmSubtractSky_SOURCES = tst_pmSubtractSky.c
 
 check_PROGRAMS = $(TESTS)