add openssl m4

configure.ac

@@ -20,7 +20,7 @@ dnl Checks for libev
 m4_include([libev/libev.m4])
 
 dnl Checks for openssl
-AC_SEARCH_LIBS([MD5], [crypto], [ ], AC_MSG_ERROR([libcrypto not found.]))
+ss_OPENSSL
 
 dnl Checks for host.
 AC_MSG_CHECKING(for what kind of host)

m4/openssl.m4

@@ -0,0 +1,56 @@
+dnl Check to find the OpenSSL headers/libraries
+
+AC_DEFUN([ss_OPENSSL],
+[
+  case $host_os in
+    *mingw*)
+    ;;
+    *)
+      AC_CHECK_FUNC(dlopen,
+        [],
+        [AC_CHECK_LIB(dl, dlopen,
+          [LIBS="$LIBS -ldl"],
+          [AC_MSG_ERROR([OpenSSL depends on libdl.]); break]
+        )]
+      )
+    ;;
+  esac
+
+  AC_ARG_WITH(openssl,
+    AS_HELP_STRING([--with-openssl=DIR], [OpenSSL base directory, or:]),
+    [openssl="$withval"
+     CFLAGS="$CFLAGS -I$withval/include"
+     LDFLAGS="$LDFLAGS -L$withval/lib"]
+  )
+
+  AC_ARG_WITH(openssl-include,
+    AS_HELP_STRING([--with-openssl-include=DIR], [OpenSSL headers directory (without trailing /openssl)]),
+    [openssl_include="$withval"
+     CFLAGS="$CFLAGS -I$withval"]
+  )
+
+  AC_ARG_WITH(openssl-lib,
+    AS_HELP_STRING([--with-openssl-lib=DIR], [OpenSSL library directory]),
+    [openssl_lib="$withval"
+     LDFLAGS="$LDFLAGS -L$withval"]
+  )
+
+  AC_CHECK_HEADERS(openssl/evp.h openssl/rsa.h openssl/rand.h openssl/err.h openssl/sha.h openssl/pem.h openssl/engine.h,
+    [],
+    [AC_MSG_ERROR([OpenSSL header files not found.]); break]
+  )
+
+  AC_CHECK_LIB(crypto, EVP_EncryptInit_ex,
+    [LIBS="-lcrypto $LIBS"],
+    [AC_MSG_ERROR([OpenSSL libraries not found.])]
+  )
+
+  AC_CHECK_FUNCS([RAND_pseudo_bytes EVP_EncryptInit_ex], ,
+    [AC_MSG_ERROR([Missing OpenSSL functionality, make sure you have installed the latest version.]); break],
+  )
+
+  AC_CHECK_DECL([OpenSSL_add_all_algorithms], ,
+    [AC_MSG_ERROR([Missing OpenSSL functionality, make sure you have installed the latest version.]); break],
+    [#include <openssl/evp.h>]
+  )
+])