Fix PyPy by eliminating deprecated library detection code

PyPy fails when handled here as a special case.

For example, the correct value for libname may be "pypy3.9-c" and
can be inferred from LDLIBRARY, but setting it to "pypy3-c" leads to
failure with `ld: cannot find -lpypy3-c: No such file or directory`.

Author: maresb

pytensor/link/c/cmodule.py

@@ -1751,30 +1751,23 @@ def std_lib_dirs_and_libs() -> Optional[tuple[list[str], ...]]:
     elif sys.platform == "darwin":
         std_lib_dirs_and_libs.data = [], []
     else:
-        if platform.python_implementation() == "PyPy":
-            # Assume Linux (note: Ubuntu doesn't ship this .so)
-            libname = "pypy3-c"
-            # Unfortunately the only convention of this .so is that it appears
-            # next to the location of the interpreter binary.
-            libdir = os.path.dirname(os.path.realpath(sys.executable))
-        else:
-            # Assume Linux
-            # Typical include directory: /usr/include/python2.6
+        # Assume Linux
+        # Typical include directory: /usr/include/python2.6
 
-            # get the name of the python library (shared object)
+        # get the name of the python library (shared object)
 
-            libname = str(get_config_var("LDLIBRARY"))
+        libname = str(get_config_var("LDLIBRARY"))
 
-            if libname.startswith("lib"):
-                libname = libname[3:]
+        if libname.startswith("lib"):
+            libname = libname[3:]
 
-            # remove extension if present
-            if libname.endswith(".so"):
-                libname = libname[:-3]
-            elif libname.endswith(".a"):
-                libname = libname[:-2]
+        # remove extension if present
+        if libname.endswith(".so"):
+            libname = libname[:-3]
+        elif libname.endswith(".a"):
+            libname = libname[:-2]
 
-            libdir = str(get_config_var("LIBDIR"))
+        libdir = str(get_config_var("LIBDIR"))
 
         std_lib_dirs_and_libs.data = [libname], [libdir]