From c51d1cfe9a58a0427af2a9a0f78e4806934600f3 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Tue, 16 Aug 2022 13:44:19 +0100
Subject: [PATCH] m4: Check for GNU realpath program

It is a dependency of the ocaml-dep.sh script, required for all builds.
---
 docs/guestfs-building.pod | 4 ++++
 m4/guestfs-progs.m4       | 5 +++++
 ocaml-dep.sh.in           | 8 ++++----
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/docs/guestfs-building.pod b/docs/guestfs-building.pod
index f64352dc4..7874033f2 100644
--- a/docs/guestfs-building.pod
+++ b/docs/guestfs-building.pod
@@ -142,6 +142,10 @@ I<Required>.
 
 I<Required>.
 
+=item realpath
+
+I<Required>.
+
 =item flex
 
 =item bison
diff --git a/m4/guestfs-progs.m4 b/m4/guestfs-progs.m4
index 22fc61367..10ed96a7e 100644
--- a/m4/guestfs-progs.m4
+++ b/m4/guestfs-progs.m4
@@ -49,6 +49,11 @@ AC_CHECK_PROG([GPERF],[gperf],[gperf],[no])
 test "x$GPERF" = "xno" &&
     AC_MSG_ERROR([gperf must be installed])
 
+dnl Check for realpath (used by ocaml-dep.sh for basic builds).
+AC_CHECK_PROGS([REALPATH],[grealpath realpath],[no])
+test "x$REALPATH" = "xno" &&
+    AC_MSG_ERROR([GNU realpath program must be installed])
+
 dnl Check for xorriso/genisoimage/mkisofs.
 AC_PATH_PROGS([MKISOFS],[xorrisofs genisoimage mkisofs],[no],
     [$PATH$PATH_SEPARATOR/usr/sbin$PATH_SEPARATOR/sbin])
diff --git a/ocaml-dep.sh.in b/ocaml-dep.sh.in
index 21bf3812a..866f48db8 100755
--- a/ocaml-dep.sh.in
+++ b/ocaml-dep.sh.in
@@ -44,10 +44,10 @@ ocaml
 # Output file is always created in the current directory.
 output=.depend
 
-subdir=$(realpath --relative-to=@abs_top_builddir@ .)
-srcdir=$(realpath --relative-to=. @abs_top_srcdir@/${subdir})
-srcdir_re=$(realpath --relative-to=. @abs_top_srcdir@/${subdir} | sed 's/\./[.]/g')
-top_builddir=$(realpath --relative-to=. @abs_top_builddir@)
+subdir=$(@REALPATH@ --relative-to=@abs_top_builddir@ .)
+srcdir=$(@REALPATH@ --relative-to=. @abs_top_srcdir@/${subdir})
+srcdir_re=$(@REALPATH@ --relative-to=. @abs_top_srcdir@/${subdir} | sed 's/\./[.]/g')
+top_builddir=$(@REALPATH@ --relative-to=. @abs_top_builddir@)
 
 includes="-I @abs_top_srcdir@/$subdir -I @abs_top_builddir@/$subdir"
 for i in $include_dirs; do