Update git to @2.14.1, requires pcre+jit variant (#5430)

Update the git package to git@2.14.1.

This requires a pcre that has been built with `--enable-jit`, so this
adds a variant to pcre to support that and arranges so that git versions
before 2.14 depend on pcre and git 2.14 and after depend on pcre+jit.

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

@@ -43,6 +43,11 @@ class Git(AutotoolsPackage):
     #       https://www.kernel.org/pub/software/scm/git/git-manpages-{version}.tar.xz
 
     releases = [
+        {
+            'version': '2.14.1',
+            'md5': 'e965a37b3d277f2e7e78f5b04de28e2a',
+            'md5_manpages': 'da2e75ea3972b9e93fb47023e3bf1401',
+        },
         {
             'version': '2.13.0',
             'md5': 'd0f14da0ef1d22f1ce7f7876fadcb39f',
@@ -145,7 +150,8 @@ class Git(AutotoolsPackage):
     depends_on('gettext')
     depends_on('libiconv')
     depends_on('openssl')
-    depends_on('pcre')
+    depends_on('pcre', when='@:2.13')
+    depends_on('pcre+jit', when='@2.14:')
     depends_on('perl')
     depends_on('zlib')
 

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

@@ -39,6 +39,9 @@ class Pcre(AutotoolsPackage):
 
     patch('intel.patch', when='@8.38')
 
+    variant('jit', default=False,
+            description='Enable JIT support.')
+
     variant('utf', default=True,
             description='Enable support for UTF-8/16/32, '
             'incompatible with EBCDIC.')
@@ -46,6 +49,9 @@ class Pcre(AutotoolsPackage):
     def configure_args(self):
         args = []
 
+        if '+jit' in self.spec:
+            args.append('--enable-jit')
+
         if '+utf' in self.spec:
             args.append('--enable-utf')
             args.append('--enable-unicode-properties')