build: Make digest function checks conditional on their use

The digest function checks where unconditionally requiring the functions
to exist or they would error out. But these functions are not required
on all systems, they depend on the ABI to be exposed.

diff --git a/configure.ac b/configure.ac
index 91e8fbf66a3a820f46bad26858960811baf94ebf..a6e63db676a908726016258bc15b519ca5933f01 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -44,7 +44,7 @@ need_err=yes
 need_errc=yes
 need_fpurge=yes
 need_funopen=yes
-need_md5=yes
+need_md5=no
 need_name_from_id=yes
 need_nlist=yes
 need_progname=yes
@@ -169,20 +169,28 @@ AM_CONDITIONAL([HAVE_LIBTESTU01],
   [test "x$ac_cv_lib_testu01_unif01_CreateExternGenBits" = "xyes"])
 
 saved_LIBS="$LIBS"
-AC_SEARCH_LIBS([MD5Update], [md], [
-  AS_IF([test "x$ac_cv_search_MD5Update" != "xnone required"], [
-    MD5_LIBS="$MD5_LIBS $ac_cv_search_MD5Update"
-    need_transparent_libmd=yes
+AS_IF([test "$need_md5" = "yes"], [
+  AC_SEARCH_LIBS([MD5Update], [md], [
+    AS_IF([test "x$ac_cv_search_MD5Update" != "xnone required"], [
+      MD5_LIBS="$MD5_LIBS $ac_cv_search_MD5Update"
+      need_transparent_libmd=yes
+    ])
+  ], [
+    AC_MSG_ERROR([cannot find required MD5 functions in libc or libmd])
   ])
-], [
-  AC_MSG_ERROR([cannot find required MD5 functions in libc or libmd])
 ])
-AC_SEARCH_LIBS([SHA512Update], [md], [
-  AS_IF([test "x$ac_cv_search_SHA512Update" != "xnone required"], [
-    LIBBSD_LIBS="$LIBBSD_LIBS $ac_cv_search_SHA512Update"
+AS_IF([test "$need_arc4random" = "yes"], [
+  AC_CHECK_FUNCS([getentropy])
+
+  AS_IF([test "$ac_cv_func_getentropy" != "yes"], [
+    AC_SEARCH_LIBS([SHA512Update], [md], [
+      AS_IF([test "x$ac_cv_search_SHA512Update" != "xnone required"], [
+        LIBBSD_LIBS="$SHA512_LIBS $ac_cv_search_SHA512Update"
+      ])
+    ], [
+      AC_MSG_ERROR([cannot find required SHA-2 functions in libc or libmd])
+    ])
   ])
-], [
-  AC_MSG_ERROR([cannot find required SHA-2 functions in libc or libmd])
 ])
 LIBS="$saved_LIBS"