Use ENV.cc and ENV.cxx where appropriate

Cursory testing shows that these all build with llvm and those that have
binaries work. Formulae should be marked 'fails_with_llvm' if there are
issues found later.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Formula/connect.rb

@@ -7,7 +7,7 @@ class Connect < Formula
   md5 '5165e2fcd2cf58899f34878fe6b447c6'
 
   def install
-    system "gcc", "connect.c", "-o", "connect", "-lresolv"
+    system "#{ENV.cc}", "connect.c", "-o", "connect", "-lresolv"
     bin.install "connect"
   end
 end

Formula/cups-pdf.rb

@@ -9,7 +9,7 @@ class CupsPdf < Formula
   def patches; DATA; end
 
   def install
-    system "gcc -O9 -o cups-pdf src/cups-pdf.c"
+    system "#{ENV.cc} #{ENV.cflags} -o cups-pdf src/cups-pdf.c"
 
     (etc+'cups').install "extra/cups-pdf.conf"
     (lib+'cups/backend').install "cups-pdf"

Formula/gforth.rb

@@ -9,7 +9,7 @@ class Gforth < Formula
     ENV.j1 # Parallel builds won't work
     # Install 32-bit only, even on Snow Leopard. See:
     # http://www.groupsrv.com/computers/about648918.html
-    ENV['CC'] = "gcc -m32"
+    ENV['CC'] = "#{ENV.cc} -m32"
     system "./configure", "--disable-debug", "--disable-dependency-tracking", "--prefix=#{prefix}"
     system "make" # Separate build steps.
     system "make install"

Formula/ldid.rb

@@ -6,7 +6,7 @@ class Ldid < Formula
   md5 '634c2f8b8a084046883e3793f6580e07'
 
   def install
-    system "g++ -I . -o util/ldid{,.cpp} -x c util/{lookup2,sha1}.c"
+    system "#{ENV.cxx} -I . -o util/ldid{,.cpp} -x c util/{lookup2,sha1}.c"
     bin.install ["util/ldid"]
   end
 end

Formula/tth.rb

@@ -7,7 +7,7 @@ class Tth < Formula
   version '4.00'
 
   def install
-    system 'gcc -Os -o tth tth.c'
+    system "#{ENV.cc} -o tth tth.c"
     bin.install %w(tth latex2gif ps2gif ps2png)
     man1.install 'tth.1'
   end

Formula/yamdi.rb

@@ -6,7 +6,7 @@ class Yamdi < Formula
   md5 '3f8395373e941f235015a92d4da047c8'
 
   def install
-    system "gcc yamdi.c -o yamdi -O2 -Wall"
+    system "#{ENV.cc} #{ENV.cflags} yamdi.c -o yamdi"
     bin.install "yamdi"
     man1.install "man1/yamdi.1"
   end