rename option: llvm-support -> llvm

Formula/mesa.rb

@@ -11,7 +11,7 @@ class Mesa < Formula
 
   option "without-test", "Skip compile-time tests"
   option "with-static", "Build static libraries (not recommended)"
-  option "with-llvm-support", "Build with extra drivers. Requires LLVM and Libelf"
+  option "with-llvm", "Build drivers that require llvm and libelf"
 
   depends_on "autoconf" => :build
   depends_on "automake" => :build
@@ -22,6 +22,7 @@ class Mesa < Formula
   depends_on "libtool" => :build
   depends_on "linuxbrew/xorg/libpthread-stubs" => :build
 
+  depends_on "llvm" => :optional
   depends_on "linuxbrew/xorg/wayland" => :optional
   depends_on "linuxbrew/xorg/libglvnd" => :optional
   depends_on "linuxbrew/xorg/libvdpau" => :optional
@@ -32,12 +33,9 @@ class Mesa < Formula
   depends_on "linuxbrew/xorg/libomxil-bellagio"
   depends_on "linuxbrew/xorg/libdrm"
 
-  if build.with? "llvm-support"
-    depends_on "llvm"
-    depends_on "libelf" # radeonsi requires libelf when using llvm
-    # Revisit later [@maxim-belkin, March 6, 2018]
-    # depends_on "linuxbrew/xorg/wayland-protocols" => :recommended
-  end
+  depends_on "libelf" if build.with? "llvm" # radeonsi requires libelf when using llvm
+  # Revisit later [@maxim-belkin, March 6, 2018]
+  # depends_on "linuxbrew/xorg/wayland-protocols" => :recommended
 
   # There is a circular dependency between Mesa and libva:
   # libva should be installed:
@@ -96,7 +94,7 @@ def install
       --with-swr-archs=avx,avx2,knl,skx
     ]
 
-    if build.with? "llvm-support"
+    if build.with? "llvm"
       args << %W[
         --enable-llvm
         --with-gallium-drivers=i915,nouveau,r300,r600,radeonsi,svga,swrast,swr