diff --git a/ChangeLog b/ChangeLog
index f45022e..86cb345 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2024-07-21  Bruno Haible  <bruno@clisp.org>
+
+	build: Fix VPATH builds.
+	* doc/Makefile.in (TEXINFO): Look up texi2html in the current directory.
+	(gperf.1): Look up help2man in the source directory. Generate gperf.1 in
+	the source directory.
+
 2024-07-21  Bruno Haible  <bruno@clisp.org>
 
 	build: Fix use of perl on Guix, FreeBSD, NetBSD.
diff --git a/doc/Makefile.in b/doc/Makefile.in
index 4f93405..03f40c8 100644
--- a/doc/Makefile.in
+++ b/doc/Makefile.in
@@ -49,7 +49,7 @@ TEXI2DVI = texi2dvi
 DVIPS = dvips -D600
 TEXI2PDF = texi2pdf
 MAKEINFO = LANG= LC_MESSAGES= LC_ALL= LANGUAGE= makeinfo -c CHECK_NORMAL_MENU_STRUCTURE=1
-TEXI2HTML = perl $(srcdir)/texi2html
+TEXI2HTML = perl texi2html
 TEXI2ANY = texi2any
 
 # Programs used by "make install":
@@ -114,7 +114,7 @@ gperf_0.html : $(srcdir)/gperf.texi $(srcdir)/gpl-3.0.texi
 man : gperf.1
 
 gperf.1 gperf.1-update :
-	./help2man --name='generate a perfect hash function from a key set' --section=1 ../src/gperf > gperf.1
+	$(srcdir)/help2man --name='generate a perfect hash function from a key set' --section=1 ../src/gperf > $(srcdir)/gperf.1
 
 gperf.1-update : force