add missing runtime deps to ALL core packages, add getrealdeps script (#7472)

* gcc: add missing zlibpkg dep

* add getrealdeps script

* add color

* suggested changes from @supechicken

* suggested changes

* fix verbiage

* add NOCOLORS option

* use read in lieu of head, and do not check nonexistent files

* Exit early if wrong package name is given.

* Add some quick exit code

* Allow for pkg.rb in getrealdeps and also add deps to all core packages

* fix lint error

* fix zlibpkg

* cleanup gcc deps

* move filecmd to be a ruby dependency

* fix llvm deps

* lint fix

* update more deps

* make sure package is installed before checking for deps

* add more deps

* change verbiage

* add more deps

* more dep updates

packages/gmp.rb

@@ -22,6 +22,8 @@ class Gmp < Package
      x86_64: '50847bd14c11de841c7c74696e2ff4503253bbaacd38e9ffb31814d6ccfb76f3'
   })
 
+  depends_on 'gcc' # R
+  depends_on 'glibc' # R
   no_patchelf
 
   def self.build