diff --git a/gnu/packages/cmake.scm b/gnu/packages/cmake.scm
index 2efce6fd87..d75b9f62ef 100644
--- a/gnu/packages/cmake.scm
+++ b/gnu/packages/cmake.scm
@@ -77,7 +77,7 @@ archive_write_set_format_shar.c"
                     ;; Help cmake's bootstrap process to find system libraries
                     (begin
                       (setenv "CMAKE_LIBRARY_PATH" (getenv "LIBRARY_PATH"))
-                      (setenv "CMAKE_INCLUDE_PATH" (getenv "CPATH"))
+                      (setenv "CMAKE_INCLUDE_PATH" (getenv "C_INCLUDE_PATH"))
                       ;; Get verbose output from failed tests
                       (setenv "CTEST_OUTPUT_ON_FAILURE" "TRUE")))
                   (alist-replace
diff --git a/gnu/packages/cross-base.scm b/gnu/packages/cross-base.scm
index d64cdd1272..cefe2f947f 100644
--- a/gnu/packages/cross-base.scm
+++ b/gnu/packages/cross-base.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2014, 2015 Mark H Weaver <mhw@netris.org>
 ;;;
 ;;; This file is part of GNU Guix.
@@ -181,12 +181,14 @@ may be either a libc package or #f.)"
                             (string-append libc "/lib"))
 
                     (let ((cpath   (search-path-as-string->list
-                                    (getenv "CPATH")))
+                                    (getenv "C_INCLUDE_PATH")))
                           (libpath (search-path-as-string->list
                                     (getenv "LIBRARY_PATH"))))
                       (setenv "CPATH"
                               (list->search-path-as-string
                                (remove cross? cpath) ":"))
+                      (for-each unsetenv
+                                '("C_INCLUDE_PATH" "CPLUS_INCLUDE_PATH"))
                       (setenv "LIBRARY_PATH"
                               (list->search-path-as-string
                                (remove cross? libpath) ":"))
diff --git a/gnu/packages/package-management.scm b/gnu/packages/package-management.scm
index 917464543c..b8d0c9c2ac 100644
--- a/gnu/packages/package-management.scm
+++ b/gnu/packages/package-management.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2015 Ricardo Wurmus <rekado@elephly.net>
 ;;;
 ;;; This file is part of GNU Guix.
@@ -340,7 +340,7 @@ symlinks to the files in a common directory such as /usr/local.")
                       (let ((nspr (assoc-ref inputs "nspr"))
                             (nss  (assoc-ref inputs "nss")))
                         (setenv "CPATH"
-                                (string-append (getenv "CPATH") ":"
+                                (string-append (getenv "C_INCLUDE_PATH") ":"
                                                nspr "/include/nspr:"
                                                nss "/include/nss"))
                         (setenv "LIBRARY_PATH"
diff --git a/gnu/packages/video.scm b/gnu/packages/video.scm
index f1089f76ca..63a623d05e 100644
--- a/gnu/packages/video.scm
+++ b/gnu/packages/video.scm
@@ -1057,7 +1057,7 @@ for use with HTML5 video.")
           (lambda _
             ;; Copy-paste settings from the cmake build system.
             (setenv "CMAKE_LIBRARY_PATH" (getenv "LIBRARY_PATH"))
-            (setenv "CMAKE_INCLUDE_PATH" (getenv "CPATH")))
+            (setenv "CMAKE_INCLUDE_PATH" (getenv "C_INCLUDE_PATH")))
           (alist-replace 'build
             (lambda* (#:key inputs outputs #:allow-other-keys)
               (let*
diff --git a/gnu/packages/webkit.scm b/gnu/packages/webkit.scm
index bb041b1935..d22aacd12f 100644
--- a/gnu/packages/webkit.scm
+++ b/gnu/packages/webkit.scm
@@ -80,7 +80,7 @@
             ;; that it will be in the same directory as gstreamer's header
             ;; files.
             (setenv "CPATH"
-                    (string-append (getenv "CPATH")
+                    (string-append (getenv "C_INCLUDE_PATH")
                                    ":"
                                    (assoc-ref inputs "gst-plugins-base")
                                    "/include/gstreamer-1.0")))))))