util: import sha1 implementation from OpenBSD

At the moment we support 5+ different implementations each with varying
amount of bugs - from thread safely problems [1], to outright broken
implementation(s) [2]

In order to accommodate these we have 150+ lines of configure script and
extra two configure toggles. Whist an actual implementation being
~200loc and our current compat wrapping ~250.

Let's not forget that different people use different code paths, thus
effectively makes it harder to test and debug since the default
implementation is automatically detected.

To minimise all these lovely experiences, import the "100% Public
Domain" OpenBSD sha1 implementation. Clearly document any changes needed
to get building correctly, since many/most of those can be upstreamed
making future syncs easier.

As an added bonus this will avoid all the 'fun' experiences trying to
integrate it with the Android and SCons builds.

v2: Manually expand __BEGIN_DECLS/__END_DECLS and document (Tapani).

Furthermore it seems that some games (or surrounding runtime) static
link against OpenSSL resulting in conflicts. For more information see
the discussion thread [3]

Bugzilla [1]: https://bugs.freedesktop.org/show_bug.cgi?id=94904
Bugzilla [2]: https://bugs.freedesktop.org/show_bug.cgi?id=97967
[3] https://lists.freedesktop.org/archives/mesa-dev/2017-January/140748.html
Cc: Mark Janes <mark.a.janes@intel.com>
Cc: Vinson Lee <vlee@freedesktop.org>
Cc: Tapani Pälli <tapani.palli@intel.com>
Cc: Jonathan Gray <jsg@jsg.id.au>
Tested-by: Jonathan Gray <jsg@jsg.id.au>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Tapani Pälli <tapani.palli@intel.com> (v1)
Acked-by: Jason Ekstrand <jason@jlekstrand.net> (v1)
diff --git a/configure.ac b/configure.ac
index 33f1c42..6b07b2d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -9,7 +9,6 @@
 dnl Copyright © 2011-2012 Benjamin Franzke
 dnl Copyright © 2008-2014 David Airlie
 dnl Copyright © 2009-2013 Brian Paul
-dnl Copyright © 2003-2007 Keith Packard, Daniel Stone
 dnl
 dnl Permission is hereby granted, free of charge, to any person obtaining a
 dnl copy of this software and associated documentation files (the "Software"),
@@ -1437,151 +1436,6 @@
     fi
 fi
 
-# SHA1 hashing
-AC_ARG_WITH([sha1],
-        [AS_HELP_STRING([--with-sha1=libc|libmd|libnettle|libgcrypt|libcrypto|libsha1|CommonCrypto|CryptoAPI],
-        [choose SHA1 implementation])])
-case "x$with_sha1" in
-x | xlibc | xlibmd | xlibnettle | xlibgcrypt | xlibcrypto | xlibsha1 | xCommonCrypto | xCryptoAPI)
-  ;;
-*)
-        AC_MSG_ERROR([Illegal value for --with-sha1: $with_sha1])
-esac
-
-AC_CHECK_FUNC([SHA1Init], [HAVE_SHA1_IN_LIBC=yes])
-if test "x$with_sha1" = x && test "x$HAVE_SHA1_IN_LIBC" = xyes; then
-	with_sha1=libc
-fi
-if test "x$with_sha1" = xlibc && test "x$HAVE_SHA1_IN_LIBC" != xyes; then
-	AC_MSG_ERROR([sha1 in libc requested but not found])
-fi
-if test "x$with_sha1" = xlibc; then
-	AC_DEFINE([HAVE_SHA1_IN_LIBC], [1],
-		[Use libc SHA1 functions])
-	SHA1_LIBS=""
-fi
-AC_CHECK_FUNC([CC_SHA1_Init], [HAVE_SHA1_IN_COMMONCRYPTO=yes])
-if test "x$with_sha1" = x && test "x$HAVE_SHA1_IN_COMMONCRYPTO" = xyes; then
-	with_sha1=CommonCrypto
-fi
-if test "x$with_sha1" = xCommonCrypto && test "x$HAVE_SHA1_IN_COMMONCRYPTO" != xyes; then
-	AC_MSG_ERROR([CommonCrypto requested but not found])
-fi
-if test "x$with_sha1" = xCommonCrypto; then
-	AC_DEFINE([HAVE_SHA1_IN_COMMONCRYPTO], [1],
-		[Use CommonCrypto SHA1 functions])
-	SHA1_LIBS=""
-fi
-dnl stdcall functions cannot be tested with AC_CHECK_LIB
-AC_CHECK_HEADER([wincrypt.h], [HAVE_SHA1_IN_CRYPTOAPI=yes], [], [#include <windows.h>])
-if test "x$with_sha1" = x && test "x$HAVE_SHA1_IN_CRYPTOAPI" = xyes; then
-	with_sha1=CryptoAPI
-fi
-if test "x$with_sha1" = xCryptoAPI && test "x$HAVE_SHA1_IN_CRYPTOAPI" != xyes; then
-	AC_MSG_ERROR([CryptoAPI requested but not found])
-fi
-if test "x$with_sha1" = xCryptoAPI; then
-	AC_DEFINE([HAVE_SHA1_IN_CRYPTOAPI], [1],
-		[Use CryptoAPI SHA1 functions])
-	SHA1_LIBS=""
-fi
-AC_CHECK_LIB([md], [SHA1Init], [HAVE_LIBMD=yes])
-if test "x$with_sha1" = x && test "x$HAVE_LIBMD" = xyes; then
-	with_sha1=libmd
-fi
-if test "x$with_sha1" = xlibmd && test "x$HAVE_LIBMD" != xyes; then
-	AC_MSG_ERROR([libmd requested but not found])
-fi
-if test "x$with_sha1" = xlibmd; then
-	AC_DEFINE([HAVE_SHA1_IN_LIBMD], [1],
-	          [Use libmd SHA1 functions])
-	SHA1_LIBS=-lmd
-fi
-PKG_CHECK_MODULES([LIBSHA1], [libsha1], [HAVE_LIBSHA1=yes], [HAVE_LIBSHA1=no])
-if test "x$with_sha1" = x && test "x$HAVE_LIBSHA1" = xyes; then
-   with_sha1=libsha1
-fi
-if test "x$with_sha1" = xlibsha1 && test "x$HAVE_LIBSHA1" != xyes; then
-	AC_MSG_ERROR([libsha1 requested but not found])
-fi
-if test "x$with_sha1" = xlibsha1; then
-	AC_DEFINE([HAVE_SHA1_IN_LIBSHA1], [1],
-	          [Use libsha1 for SHA1])
-	SHA1_LIBS=-lsha1
-fi
-AC_CHECK_LIB([nettle], [nettle_sha1_init], [HAVE_LIBNETTLE=yes])
-if test "x$with_sha1" = x && test "x$HAVE_LIBNETTLE" = xyes; then
-	with_sha1=libnettle
-fi
-if test "x$with_sha1" = xlibnettle && test "x$HAVE_LIBNETTLE" != xyes; then
-	AC_MSG_ERROR([libnettle requested but not found])
-fi
-if test "x$with_sha1" = xlibnettle; then
-	AC_DEFINE([HAVE_SHA1_IN_LIBNETTLE], [1],
-	          [Use libnettle SHA1 functions])
-	SHA1_LIBS=-lnettle
-fi
-AC_CHECK_LIB([gcrypt], [gcry_md_open], [HAVE_LIBGCRYPT=yes])
-if test "x$with_sha1" = x && test "x$HAVE_LIBGCRYPT" = xyes; then
-	with_sha1=libgcrypt
-fi
-if test "x$with_sha1" = xlibgcrypt && test "x$HAVE_LIBGCRYPT" != xyes; then
-	AC_MSG_ERROR([libgcrypt requested but not found])
-fi
-if test "x$with_sha1" = xlibgcrypt; then
-	AC_DEFINE([HAVE_SHA1_IN_LIBGCRYPT], [1],
-	          [Use libgcrypt SHA1 functions])
-	SHA1_LIBS=-lgcrypt
-fi
-# We don't need all of the OpenSSL libraries, just libcrypto
-AC_CHECK_LIB([crypto], [SHA1_Init], [HAVE_LIBCRYPTO=yes])
-PKG_CHECK_MODULES([OPENSSL], [openssl], [HAVE_OPENSSL_PKC=yes],
-                  [HAVE_OPENSSL_PKC=no])
-if test "x$HAVE_LIBCRYPTO" = xyes || test "x$HAVE_OPENSSL_PKC" = xyes; then
-	if test "x$with_sha1" = x; then
-		with_sha1=libcrypto
-	fi
-else
-	if test "x$with_sha1" = xlibcrypto; then
-		AC_MSG_ERROR([OpenSSL libcrypto requested but not found])
-	fi
-fi
-if test "x$with_sha1" = xlibcrypto; then
-	if test "x$HAVE_LIBCRYPTO" = xyes; then
-		SHA1_LIBS=-lcrypto
-	else
-		SHA1_LIBS="$OPENSSL_LIBS"
-		SHA1_CFLAGS="$OPENSSL_CFLAGS"
-	fi
-fi
-AC_MSG_CHECKING([for SHA1 implementation])
-AC_MSG_RESULT([$with_sha1])
-AC_SUBST(SHA1_LIBS)
-AC_SUBST(SHA1_CFLAGS)
-
-# Enable a define for SHA1
-if test "x$with_sha1" != "x"; then
-	DEFINES="$DEFINES -DHAVE_SHA1"
-fi
-
-# Allow user to configure out the shader-cache feature
-AC_ARG_ENABLE([shader-cache],
-    AS_HELP_STRING([--disable-shader-cache], [Disable binary shader cache]),
-    [enable_shader_cache="$enableval"],
-    [if test "x$with_sha1" != "x"; then
-        enable_shader_cache=yes
-     else
-        enable_shader_cache=no
-     fi])
-if test "x$with_sha1" = "x"; then
-    if test "x$enable_shader_cache" = "xyes"; then
-        AC_MSG_ERROR([Cannot enable shader cache (no SHA-1 implementation found)])
-    fi
-fi
-if test "x$enable_shader_cache" = "xyes"; then
-   AC_DEFINE([ENABLE_SHADER_CACHE], [1], [Enable shader cache])
-fi
-
 if test "x$enable_dri" = xyes; then
     require_dri_shared_libs_and_glapi "DRI"
 
@@ -1895,9 +1749,6 @@
             if test "x$HAVE_I965_DRI" != xyes; then
                 AC_MSG_ERROR([Intel Vulkan driver requires the i965 dri driver])
             fi
-            if test "x$with_sha1" == "x"; then
-                AC_MSG_ERROR([Intel Vulkan driver requires SHA1])
-            fi
             HAVE_INTEL_VULKAN=yes;
 
             ;;
@@ -1905,10 +1756,7 @@
             PKG_CHECK_MODULES([AMDGPU], [libdrm_amdgpu >= $LIBDRM_AMDGPU_REQUIRED])
             radeon_llvm_check $LLVM_REQUIRED_RADV "radv"
             HAVE_RADEON_VULKAN=yes;
-            if test "x$with_sha1" == "x"; then
-                AC_MSG_ERROR([radv vulkan driver requires SHA1])
-            fi
-	    ;;
+            ;;
         *)
             AC_MSG_ERROR([Vulkan driver '$driver' does not exist])
             ;;
@@ -2972,13 +2820,6 @@
     echo "        HUD lmsensors:   yes"
 fi
 
-dnl Shader cache
-echo ""
-echo "        Shader cache:    $enable_shader_cache"
-if test "x$enable_shader_cache" = "xyes"; then
-    echo "        With SHA1 from:  $with_sha1"
-fi
-
 dnl Libraries
 echo ""
 echo "        Shared libs:     $enable_shared"