Make deps: Updated required list of dependencies for macOS

It was possible to drop `nasm` from the list of required macOS dependencies. However, `pkg-config` had to be added - it was required before but probably no one noticed this.

In order to build `external_clang` successfully, `external_xml2` had to be added to the clang dependencies (`c-index-test` was failing).

Note: On Linux `make deps` still seems to require `nasm` installed via apt.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D8870

build_files/build_environment/CMakeLists.txt

@@ -30,7 +30,7 @@
 #   build_deps 2015 x64 / build_deps 2015 x86
 #
 # MAC OS X USAGE:
-#   Install with homebrew: brew install cmake autoconf automake libtool yasm nasm bison
+#   Install with homebrew: brew install autoconf automake bison cmake libtool pkg-config yasm
 #   Run "make deps" from main Blender directory
 #
 # LINUX USAGE:

build_files/build_environment/cmake/check_software.cmake

@@ -26,11 +26,11 @@ if(UNIX)
   set(_required_software
     autoconf
     automake
-    ${_libtoolize_name}
-    nasm
-    yasm
-    tclsh
     bison
+    ${_libtoolize_name}
+    pkg-config
+    tclsh
+    yasm
   )
 
   foreach(_software ${_required_software})
@@ -57,7 +57,7 @@ if(UNIX)
       "  apt install autoconf automake libtool yasm nasm tcl\n"
       "\n"
       "On macOS (with homebrew):\n"
-      "  brew install cmake autoconf automake libtool yasm nasm bison\n"
+      "  brew install autoconf automake bison libtool pkg-config yasm\n"
       "\n"
       "Other platforms:\n"
       "  Install equivalent packages.\n")

build_files/build_environment/cmake/clang.cmake

@@ -62,5 +62,6 @@ endif()
 
 add_dependencies(
   external_clang
+  external_xml2
   ll
 )