diff --git a/configure.in b/configure.in
index 65187b54..c6859f1d 100644
--- a/configure.in
+++ b/configure.in
@@ -2,6 +2,7 @@ dnl Process this file with autoconf to produce a configure script.
 AC_INIT(vpath.c)		dnl A distinctive file to look for in srcdir.
 AC_CONFIG_HEADER(config.h)
 
+AC_PROG_CC
 AC_PROG_INSTALL
 AC_PROG_RANLIB
 AC_PROG_CPP			dnl Later checks need this.
@@ -21,7 +22,8 @@ AC_MINUS_C_MINUS_O
 AC_SUBST(LIBOBJS)
 
 AC_HAVE_FUNCS(getdtablesize sys_siglist _sys_siglist \
-	      dup2 getcwd sigsetmask getgroups setlinebuf)
+	      dup2 getcwd sigsetmask getgroups setlinebuf \
+	      setreuid setregid)
 AC_ALLOCA
 AC_VFORK
 AC_SETVBUF_REVERSED