allow global suppression of link flags (#3592)

CRYPTOGRAPHY_SUPPRESS_LINK_FLAGS will now suppress link flags regardless
of platform. Additionally, CRYPTOGRAPHY_WINDOWS_LINK_LEGACY_OPENSSL is
now the flag you need if you want to link against < 1.1.0 on windows.

1 files changed, 11 insertions, 24 deletions

diff --git a/src/_cffi_src/build_openssl.py b/src/_cffi_src/build_openssl.py
index 7e8fb34b..853f4488 100644
--- a/src/_cffi_src/build_openssl.py
+++ b/src/_cffi_src/build_openssl.py
@@ -13,27 +13,22 @@ from _cffi_src.utils import (
 
 
 def _get_openssl_libraries(platform):
+    if os.environ.get("CRYPTOGRAPHY_SUPPRESS_LINK_FLAGS", None):
+        return []
     # OpenSSL goes by a different library name on different operating systems.
-    if platform == "darwin":
-        return _osx_libraries(
-            os.environ.get("CRYPTOGRAPHY_OSX_NO_LINK_FLAGS")
-        )
-    elif platform == "win32":
-        windows_link_openssl110 = os.environ.get(
-            "CRYPTOGRAPHY_WINDOWS_LINK_OPENSSL110", None
+    if platform == "win32" and compiler_type() == "msvc":
+        windows_link_legacy_openssl = os.environ.get(
+            "CRYPTOGRAPHY_WINDOWS_LINK_LEGACY_OPENSSL", None
         )
-        if compiler_type() == "msvc":
-            if windows_link_openssl110 is not None:
-                # Link against the 1.1.0 names
-                libs = ["libssl", "libcrypto"]
-            else:
-                # Link against the 1.0.2 and lower names
-                libs = ["libeay32", "ssleay32"]
+        if windows_link_legacy_openssl is None:
+            # Link against the 1.1.0 names
+            libs = ["libssl", "libcrypto"]
         else:
-            # Support mingw, which behaves unix-like and prefixes "lib"
-            libs = ["ssl", "crypto"]
+            # Link against the 1.0.2 and lower names
+            libs = ["libeay32", "ssleay32"]
         return libs + ["advapi32", "crypt32", "gdi32", "user32", "ws2_32"]
     else:
+        # darwin, linux, mingw all use this path
         # In some circumstances, the order in which these libs are
         # specified on the linker command-line is significant;
         # libssl must come before libcrypto
@@ -41,14 +36,6 @@ def _get_openssl_libraries(platform):
         return ["ssl", "crypto"]
 
 
-def _osx_libraries(build_static):
-    # For building statically we don't want to pass the -lssl or -lcrypto flags
-    if build_static == "1":
-        return []
-    else:
-        return ["ssl", "crypto"]
-
-
 ffi = build_ffi_for_binding(
     module_name="_openssl",
     module_prefix="_cffi_src.openssl.",