Fail with a more useful error if "ar" is not found.

configure

@@ -6038,6 +6038,9 @@ else
   RANLIB="$ac_cv_prog_RANLIB"
 fi
 
+if test X"$AR" = X"false"; then
+    as_fn_error "the \"ar\" utility is required to build sudo" "$LINENO" 5
+fi
 
 if test "x$ac_cv_prog_cc_c89" = "xno"; then
     as_fn_error "Sudo version $PACKAGE_VERSION requires an ANSI C compiler to build." "$LINENO" 5
@@ -6748,13 +6751,13 @@ if test "${lt_cv_nm_interface+set}" = set; then :
 else
   lt_cv_nm_interface="BSD nm"
   echo "int some_variable = 0;" > conftest.$ac_ext
-  (eval echo "\"\$as_me:6751: $ac_compile\"" >&5)
+  (eval echo "\"\$as_me:6754: $ac_compile\"" >&5)
   (eval "$ac_compile" 2>conftest.err)
   cat conftest.err >&5
-  (eval echo "\"\$as_me:6754: $NM \\\"conftest.$ac_objext\\\"\"" >&5)
+  (eval echo "\"\$as_me:6757: $NM \\\"conftest.$ac_objext\\\"\"" >&5)
   (eval "$NM \"conftest.$ac_objext\"" 2>conftest.err > conftest.out)
   cat conftest.err >&5
-  (eval echo "\"\$as_me:6757: output\"" >&5)
+  (eval echo "\"\$as_me:6760: output\"" >&5)
   cat conftest.out >&5
   if $GREP 'External.*some_variable' conftest.out > /dev/null; then
     lt_cv_nm_interface="MS dumpbin"
@@ -7959,7 +7962,7 @@ ia64-*-hpux*)
   ;;
 *-*-irix6*)
   # Find out which ABI we are using.
-  echo '#line 7962 "configure"' > conftest.$ac_ext
+  echo '#line 7965 "configure"' > conftest.$ac_ext
   if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
   (eval $ac_compile) 2>&5
   ac_status=$?
@@ -9351,11 +9354,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:9354: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:9357: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:9358: \$? = $ac_status" >&5
+   echo "$as_me:9361: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -9690,11 +9693,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:9693: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:9696: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:9697: \$? = $ac_status" >&5
+   echo "$as_me:9700: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -9795,11 +9798,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:9798: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:9801: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:9802: \$? = $ac_status" >&5
+   echo "$as_me:9805: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
@@ -9850,11 +9853,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:9853: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:9856: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:9857: \$? = $ac_status" >&5
+   echo "$as_me:9860: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
@@ -12217,7 +12220,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 12220 "configure"
+#line 12223 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -12313,7 +12316,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 12316 "configure"
+#line 12319 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H

configure.in

@@ -1322,6 +1322,9 @@ AC_SEARCH_LIBS([strerror], [cposix])
 AC_PROG_CPP
 AC_CHECK_TOOL(AR, ar, false)
 AC_CHECK_TOOL(RANLIB, ranlib, :)
+if test X"$AR" = X"false"; then
+    AC_MSG_ERROR([the "ar" utility is required to build sudo])
+fi
 
 if test "x$ac_cv_prog_cc_c89" = "xno"; then
     AC_MSG_ERROR([Sudo version $PACKAGE_VERSION requires an ANSI C compiler to build.])