https://bugs.gentoo.org/844868
https://bz.apache.org/bugzilla/show_bug.cgi?id=66130
--- a/build/aix/buildaix.ksh
+++ b/build/aix/buildaix.ksh
@@ -26,14 +26,14 @@ export CFLAGS='-O2 -qlanglvl=extc99'
 lslpp -L bos.adt.insttools >/dev/null
  [[ $? -ne 0 ]] && echo "must have bos.adt.insttools installed" && exit -1
 
-apr_config=`which apr-1-config`
-apu_config=`which apu-1-config`
+apr_config=`command -v apr-1-config 2>/dev/null`
+apu_config=`command -v apu-1-config 2>/dev/null`
 
 if [[ -z ${apr_config} && -z ${apu_config} ]]
 then
 	export PATH=/opt/bin:${PATH}
-	apr_config=`which apr-1-config`
-	apu_config=`which apu-1-config`
+	apr_config=`command -v apr-1-config 2>/dev/null`
+	apu_config=`command -v apu-1-config 2>/dev/null`
 fi
 
 while test $# -gt 0
--- a/build/pkg/buildpkg.sh
+++ b/build/pkg/buildpkg.sh
@@ -24,8 +24,8 @@ PREFIX=/usr/local/apache2
 TEMPDIR=/var/tmp/$USER/httpd-root
 rm -rf $TEMPDIR
 
-apr_config=`which apr-1-config`
-apu_config=`which apu-1-config`
+apr_config=`command -v apr-1-config 2>/dev/null`
+apu_config=`command -v apu-1-config 2>/dev/null`
 
 while test $# -gt 0 
 do
--- a/configure.in
+++ b/configure.in
@@ -216,13 +216,13 @@ AC_ARG_WITH(pcre,
 APACHE_HELP_STRING(--with-pcre=PATH,Use external PCRE library))
 if test "x$with_pcre" = "x" || test "$with_pcre" = "yes"; then
   with_pcre="$PATH"
-else if which $with_pcre 2>/dev/null; then :; else
+else if command -v $with_pcre 2>/dev/null; then :; else
   with_pcre="$with_pcre/bin:$with_pcre"
 fi
 fi
 
 AC_CHECK_TARGET_TOOLS(PCRE_CONFIG, [pcre2-config pcre-config],
-                      [`which $with_pcre 2>/dev/null`], $with_pcre)
+                      [`command -v $with_pcre 2>/dev/null`], $with_pcre)
 
 if test "x$PCRE_CONFIG" != "x"; then
   if $PCRE_CONFIG --version >/dev/null 2>&1; then :; else