Add a modern linux-x86 config target

'linux-x86' is similar to 'linux-x86_64' but uses -m32 rather than -m64.
Reviewed-by: NAndy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1924)

Configurations/10-main.conf

@@ -731,6 +731,8 @@ sub vms_info {
     },
 
     #### IA-32 targets...
+    #### These two targets are a bit aged and are to be used on older Linux
+    #### machines where gcc doesn't understand -m32 and -m64
     "linux-elf" => {
         inherit_from     => [ "linux-generic32", asm("x86_elf_asm") ],
         cflags           => add(picker(default => "-DL_ENDIAN",
@@ -748,6 +750,21 @@ sub vms_info {
         perlasm_scheme   => "a.out",
     },
 
+    #### X86 / X86_64 targets
+    "linux-x86" => {
+        inherit_from     => [ "linux-generic32", asm("x86_asm") ],
+        cflags           => add(picker(default => "-m32 -DL_ENDIAN",
+                                       release => "-fomit-frame-pointer")),
+        bn_ops           => "BN_LLONG",
+        perlasm_scheme   => "elf",
+        shared_ldflag    => add("-m32"),
+    },
+    "linux-x86-clang" => {
+        inherit_from     => [ "linux-x86" ],
+        cc               => "clang",
+        cxx              => "clang++",
+        cflags           => add("-Wextra -Qunused-arguments"),
+    },
     "linux-x86_64" => {
         inherit_from     => [ "linux-generic64", asm("x86_64_asm") ],
         cflags           => add("-m64 -DL_ENDIAN"),