@@ -, +, @@ 
 filenames (mostly for windows) (GH-4630)"
---
 pyximport/_pyximport2.py | 26 ++++++--------------------
 pyximport/_pyximport3.py | 26 ++++++--------------------
 2 files changed, 12 insertions(+), 40 deletions(-)
--- a/pyximport/_pyximport2.py	
+++ a/pyximport/_pyximport2.py	
@@ -185,26 +185,12 @@ def build_module(name, pyxfilename, pyxbuild_dir=None, inplace=False, language_l
     build_in_temp = sargs.pop('build_in_temp',build_in_temp)
 
     from . import pyxbuild
-    olddir = os.getcwd()
-    common = ''
-    if pyxbuild_dir:
-        # Windows concatenates the pyxbuild_dir to the pyxfilename when
-        # compiling, and then complains that the filename is too long
-        common = os.path.commonprefix([pyxbuild_dir, pyxfilename])
-    if len(common) > 30:
-        pyxfilename = os.path.relpath(pyxfilename)
-        pyxbuild_dir = os.path.relpath(pyxbuild_dir)
-        os.chdir(common)
-    try:
-        so_path = pyxbuild.pyx_to_dll(pyxfilename, extension_mod,
-                                      build_in_temp=build_in_temp,
-                                      pyxbuild_dir=pyxbuild_dir,
-                                      setup_args=sargs,
-                                      inplace=inplace,
-                                      reload_support=pyxargs.reload_support)
-    finally:
-        os.chdir(olddir)
-    so_path = os.path.join(common, so_path)
+    so_path = pyxbuild.pyx_to_dll(pyxfilename, extension_mod,
+                                  build_in_temp=build_in_temp,
+                                  pyxbuild_dir=pyxbuild_dir,
+                                  setup_args=sargs,
+                                  inplace=inplace,
+                                  reload_support=pyxargs.reload_support)
     assert os.path.exists(so_path), "Cannot find: %s" % so_path
 
     junkpath = os.path.join(os.path.dirname(so_path), name+"_*")  #very dangerous with --inplace ? yes, indeed, trying to eat my files ;)
--- a/pyximport/_pyximport3.py	
+++ a/pyximport/_pyximport3.py	
@@ -183,26 +183,12 @@ def build_module(name, pyxfilename, pyxbuild_dir=None, inplace=False, language_l
     build_in_temp = sargs.pop('build_in_temp',build_in_temp)
 
     from . import pyxbuild
-    olddir = os.getcwd()
-    common = ''
-    if pyxbuild_dir:
-        # Windows concatenates the pyxbuild_dir to the pyxfilename when
-        # compiling, and then complains that the filename is too long
-        common = os.path.commonprefix([pyxbuild_dir, pyxfilename])
-    if len(common) > 30:
-        pyxfilename = os.path.relpath(pyxfilename)
-        pyxbuild_dir = os.path.relpath(pyxbuild_dir)
-        os.chdir(common)
-    try:
-        so_path = pyxbuild.pyx_to_dll(pyxfilename, extension_mod,
-                                      build_in_temp=build_in_temp,
-                                      pyxbuild_dir=pyxbuild_dir,
-                                      setup_args=sargs,
-                                      inplace=inplace,
-                                      reload_support=pyxargs.reload_support)
-    finally:
-        os.chdir(olddir)
-    so_path = os.path.join(common, so_path)
+    so_path = pyxbuild.pyx_to_dll(pyxfilename, extension_mod,
+                                  build_in_temp=build_in_temp,
+                                  pyxbuild_dir=pyxbuild_dir,
+                                  setup_args=sargs,
+                                  inplace=inplace,
+                                  reload_support=pyxargs.reload_support)
     assert os.path.exists(so_path), "Cannot find: %s" % so_path
 
     junkpath = os.path.join(os.path.dirname(so_path), name+"_*")  #very dangerous with --inplace ? yes, indeed, trying to eat my files ;)
--