pixman: add shared, pic variants (#44889)

* Add shared/pic variants to pixman
* add +shared~pic conflict

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

@@ -31,6 +31,11 @@ class Pixman(AutotoolsPackage):
     depends_on("bison@3:", type="build")
     depends_on("libpng")
 
+    variant("shared", default=True, description="Build shared library")
+    variant("pic", default=False, description="Enable position-independent code")
+
+    conflicts("+shared ~pic")
+
     # As discussed here:
     # https://bugs.freedesktop.org/show_bug.cgi?id=104886
     # __builtin_shuffle was removed in clang 5.0.
@@ -60,7 +65,9 @@ def patch_config_h_for_intel(self):
 
     @property
     def libs(self):
-        return find_libraries("libpixman-1", self.prefix, shared=True, recursive=True)
+        return find_libraries(
+            "libpixman-1", self.prefix, shared=self.spec.satisfies("+shared"), recursive=True
+        )
 
     def configure_args(self):
         args = ["--enable-libpng", "--disable-gtk"]
@@ -78,4 +85,7 @@ def configure_args(self):
         if self.spec.satisfies("%fj"):
             args.append("--disable-arm-a64-neon")
 
+        args.extend(self.enable_or_disable("shared"))
+        args.extend(self.with_or_without("pic"))
+
         return args