ispc: external find support, added master branch version (#20033)

Co-authored-by: Massimiliano Culpo <massimiliano.culpo@gmail.com>

var/spack/repos/builtin/packages/ispc/package.py

@@ -9,6 +9,7 @@
 
 
 from spack import *
+import re
 
 
 class Ispc(CMakePackage):
@@ -18,8 +19,12 @@ class Ispc(CMakePackage):
 
     homepage = "https://ispc.github.io"
     url      = "https://github.com/ispc/ispc/tarball/v1.14.1"
+    git      = "https://github.com/ispc/ispc"
     maintainers = ['aumuell']
 
+    executables = ['^ispc$']
+
+    version('master', branch='master')
     version('1.14.1', sha256='ca12f26dafbc4ef9605487d03a2156331c1351a4ffefc9bab4d896a466880794')
     version('1.14.0', sha256='1ed72542f56738c632bb02fb0dd56ad8aec3e2487839ebbc0def8334f305a4c7')
     version('1.13.0', sha256='aca595508b51dd1ff065c406a3fd7c93822320c510077dd4d97a2b98a23f097a')
@@ -34,6 +39,7 @@ class Ispc(CMakePackage):
     depends_on('llvm@10:10.999', when='@1.13:1.13.999')
 
     patch('don-t-assume-that-ncurses-zlib-are-system-libraries.patch',
+          when='@1.14:1.14.999',
           sha256='d3ccf547d3ba59779fd375e10417a436318f2200d160febb9f830a26f0daefdc')
 
     patch('fix-linking-against-llvm-10.patch', when='@1.13:1.13.999',
@@ -47,3 +53,10 @@ def cmake_args(self):
         args.append('-DISPC_INCLUDE_TESTS=OFF')
         args.append('-DISPC_INCLUDE_UTILS=OFF')
         return args
+
+    @classmethod
+    def determine_version(cls, exe):
+        output = Executable(exe)('--version', output=str, error=str)
+        match = re.search(r'^Intel.*[iI][sS][pP][cC]\),\s+(\S+)\s+\(build.*\)',
+                          output)
+        return match.group(1) if match else None