Trac #29785: Move Extension options from src/module_list.py to "distu…

…tils:" directives in the individual files (part 3: Get rid of uname_specific)

Follow-up from #29706.

We get rid of the use of `uname_specific` to define an `Extension`
option in `module_list`, replacing it by use of `cython_aliases`.

URL: https://trac.sagemath.org/29785
Reported by: mkoeppe
Ticket author(s): Matthias Koeppe
Reviewer(s): Jonathan Kliem

src/module_list.py

@@ -116,14 +116,6 @@
 #############################################################
 
 from sage_setup.optional_extension import OptionalExtension
-UNAME = os.uname()
-
-def uname_specific(name, value, alternative):
-    if name in UNAME[0]:
-        return value
-    else:
-        return alternative
-
 
 ext_modules = [
 
@@ -501,10 +493,7 @@ def uname_specific(name, value, alternative):
               language = 'c++'),
 
     Extension('sage.libs.libecm',
-              sources = ['sage/libs/libecm.pyx'],
-              libraries = ['ecm'],
-              extra_link_args = uname_specific("Linux", ["-Wl,-z,noexecstack"],
-                                                        [])),
+              sources = ['sage/libs/libecm.pyx']),
 
     Extension('sage.libs.lrcalc.lrcalc',
               sources = ["sage/libs/lrcalc/lrcalc.pyx"]),

src/sage/env.py

@@ -412,6 +412,18 @@ def cython_aliases():
         aliases[var + "LIBEXTRA"] = list(filter(lambda s: not s.startswith(('-l','-L')), libs.split()))
         aliases[var + "LIBRARIES"] = pc['libraries']
 
+    # uname-specific flags
+    UNAME = os.uname()
+
+    def uname_specific(name, value, alternative):
+        if name in UNAME[0]:
+            return value
+        else:
+            return alternative
+
+    aliases["LINUX_NOEXECSTACK"] = uname_specific("Linux", ["-Wl,-z,noexecstack"],
+                                                  [])
+
     # LinBox needs special care because it actually requires C++11 with
     # GNU extensions: -std=c++11 does not work, you need -std=gnu++11
     # (this is true at least with GCC 7.2.0).

src/sage/libs/libecm.pyx

@@ -1,3 +1,5 @@
+# distutils: libraries = ecm
+# distutils: extra_link_args = LINUX_NOEXECSTACK
 r"""
 The Elliptic Curve Method for Integer Factorization (ECM)