Add shared/static variants to gmp and mpfr (#29836)

* Add shared/static variants to gmp and mpfr

* Update package.py

* Update package.py

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

@@ -28,6 +28,11 @@ class Gmp(AutotoolsPackage, GNUMirrorPackage):
     depends_on('libtool', type='build')
     depends_on('m4', type='build')
 
+    variant('static', default=False, description='Build static library')
+    variant('shared', default=True, description='Build shared library')
+
+    conflicts('~shared', when='~static', msg='Please select at least one of +static or +shared')
+
     # gmp's configure script seems to be broken; it sometimes misdetects
     # shared library support. Regenerating it fixes the issue.
     force_autoreconf = True
@@ -43,4 +48,9 @@ def flag_handler(self, name, flags):
         return (flags, None, None)
 
     def configure_args(self):
-        return ['--enable-cxx']
+        args = ['--enable-cxx']
+        args.extend(self.enable_or_disable('static'))
+        args.extend(self.enable_or_disable('shared'))
+        if self.spec.satisfies('+static'):
+            args.append('--with-pic')
+        return args

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

@@ -34,6 +34,11 @@ class Mpfr(AutotoolsPackage, GNUMirrorPackage):
     depends_on('autoconf-archive', when='@4.0.2:', type='build')
     depends_on('texinfo', when='@4.1.0', type='build')
 
+    variant('static', default=False, description='Build static library')
+    variant('shared', default=True, description='Build shared library')
+
+    conflicts('~static', when='~shared', msg='Please select at least one of +static or +shared')
+
     force_autoreconf = True
 
     # Check the Bugs section of old release pages for patches.
@@ -63,4 +68,8 @@ def configure_args(self):
         args = [
             '--with-gmp=' + self.spec['gmp'].prefix,
         ]
+        args.extend(self.enable_or_disable('static'))
+        args.extend(self.enable_or_disable('shared'))
+        if self.spec.satisfies('+static'):
+            args.append('--with-pic')
         return args