fpc: Fix for macOS Mojave

Closes #32629.

Signed-off-by: FX Coudert <fxcoudert@gmail.com>

Formula/fpc.rb

@@ -3,6 +3,7 @@ class Fpc < Formula
   homepage "https://www.freepascal.org/"
   url "https://downloads.sourceforge.net/project/freepascal/Source/3.0.4/fpc-3.0.4.source.tar.gz"
   sha256 "69b3b7667b72b6759cf27226df5eb54112ce3515ff5efb79d95ac14bac742845"
+  revision 1
 
   bottle do
     cellar :any_skip_relocation
@@ -16,12 +17,18 @@ class Fpc < Formula
     sha256 "a67ef5def356d122a4692e21b209c328f6d46deef4539f4d4506c3dc1eecb4b0"
   end
 
+  # Help fpc find the startup files (crt1.o and friends) with 10.14 SDK
+  patch :DATA
+
   def install
     fpc_bootstrap = buildpath/"bootstrap"
     resource("bootstrap").stage { fpc_bootstrap.install Dir["*"] }
-
     fpc_compiler = fpc_bootstrap/"ppcx64"
-    system "make", "build", "PP=#{fpc_compiler}"
+
+    # Help fpc find the startup files (crt1.o and friends) with 10.14 SDK
+    args = (MacOS.version >= :mojave) ? ['OPT="-XR/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk"'] : []
+
+    system "make", "build", "PP=#{fpc_compiler}", *args
     system "make", "install", "PP=#{fpc_compiler}", "PREFIX=#{prefix}"
 
     bin.install_symlink lib/"#{name}/#{version}/ppcx64"
@@ -46,3 +53,21 @@ class Fpc < Formula
     assert_equal "Hello Homebrew", `./hello`.strip
   end
 end
+
+__END__
+diff --git a/compiler/systems/t_bsd.pas b/compiler/systems/t_bsd.pas
+index b35a78ae..61d0817d 100644
+--- a/compiler/systems/t_bsd.pas
++++ b/compiler/systems/t_bsd.pas
+@@ -310,7 +310,10 @@ begin
+   if startupfile<>'' then
+     begin
+      if not librarysearchpath.FindFile(startupfile,false,result) then
+-       result:='/usr/lib/'+startupfile
++       if sysutils.fileexists('/usr/lib/'+startupfile) then
++         result:='/usr/lib/'+startupfile
++       else if sysutils.fileexists('/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/lib/') then
++         result:='/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/lib/'+startupfile
+     end
+   else
+     result:='';