--- a/browser/config/mozconfigs/linux32/debug-asan
+++ b/browser/config/mozconfigs/linux32/debug-asan
@@ -6,17 +6,16 @@ ac_add_options --enable-optimize="-O1"
 . $topsrcdir/build/mozconfig.stylo
 
 # ASan specific options on Linux
 ac_add_options --enable-valgrind
 
 . $topsrcdir/build/unix/mozconfig.asan
 
 export PKG_CONFIG_LIBDIR=/usr/local/lib/pkgconfig:/usr/lib/pkgconfig:/usr/share/pkgconfig
-. $topsrcdir/build/unix/mozconfig.gtk
 
 # Enable Telemetry
 export MOZ_TELEMETRY_REPORTING=1
 
 # Package js shell.
 export MOZ_PACKAGE_JSSHELL=1
 
 # Need this to prevent name conflicts with the normal nightly build packages

--- a/browser/config/mozconfigs/linux32/nightly-asan
+++ b/browser/config/mozconfigs/linux32/nightly-asan
@@ -5,17 +5,16 @@ ac_add_options --enable-optimize="-O2 -g
 . $topsrcdir/build/mozconfig.stylo
 
 # ASan specific options on Linux
 ac_add_options --enable-valgrind
 
 . $topsrcdir/build/unix/mozconfig.asan
 
 export PKG_CONFIG_LIBDIR=/usr/local/lib/pkgconfig:/usr/lib/pkgconfig:/usr/share/pkgconfig
-. $topsrcdir/build/unix/mozconfig.gtk
 
 # Package js shell.
 export MOZ_PACKAGE_JSSHELL=1
 
 # Enable Telemetry
 export MOZ_TELEMETRY_REPORTING=1
 
 # Need this to prevent name conflicts with the normal nightly build packages

--- a/browser/config/mozconfigs/linux64/debug-asan
+++ b/browser/config/mozconfigs/linux64/debug-asan
@@ -6,17 +6,16 @@ ac_add_options --enable-optimize="-O1"
 . $topsrcdir/build/mozconfig.stylo
 
 # ASan specific options on Linux
 ac_add_options --enable-valgrind
 
 . $topsrcdir/build/unix/mozconfig.asan
 
 export PKG_CONFIG_LIBDIR=/usr/local/lib64/pkgconfig:/usr/lib64/pkgconfig:/usr/share/pkgconfig
-. $topsrcdir/build/unix/mozconfig.gtk
 
 # Enable Telemetry
 export MOZ_TELEMETRY_REPORTING=1
 
 # Package js shell.
 export MOZ_PACKAGE_JSSHELL=1
 
 # Need this to prevent name conflicts with the normal nightly build packages

--- a/browser/config/mozconfigs/linux64/debug-searchfox-clang
+++ b/browser/config/mozconfigs/linux64/debug-searchfox-clang
@@ -15,11 +15,10 @@ export CXX="$topsrcdir/clang/bin/clang++
 
 # Add the static checker
 ac_add_options --enable-clang-plugin
 ac_add_options --enable-mozsearch-plugin
 
 . "$topsrcdir/build/unix/mozconfig.stdcxx"
 
 export PKG_CONFIG_LIBDIR=/usr/local/lib64/pkgconfig:/usr/lib64/pkgconfig:/usr/share/pkgconfig
-. $topsrcdir/build/unix/mozconfig.gtk
 
 . "$topsrcdir/build/mozconfig.common.override"

--- a/browser/config/mozconfigs/linux64/debug-static-analysis-clang
+++ b/browser/config/mozconfigs/linux64/debug-static-analysis-clang
@@ -14,11 +14,10 @@ export CC="$topsrcdir/clang/bin/clang"
 export CXX="$topsrcdir/clang/bin/clang++"
 
 # Add the static checker
 ac_add_options --enable-clang-plugin
 
 . "$topsrcdir/build/unix/mozconfig.stdcxx"
 
 export PKG_CONFIG_LIBDIR=/usr/local/lib64/pkgconfig:/usr/lib64/pkgconfig:/usr/share/pkgconfig
-. $topsrcdir/build/unix/mozconfig.gtk
 
 . "$topsrcdir/build/mozconfig.common.override"

--- a/browser/config/mozconfigs/linux64/hazards
+++ b/browser/config/mozconfigs/linux64/hazards
@@ -36,11 +36,10 @@ ac_add_options --without-ccache
 
 ac_add_options --disable-replace-malloc
 
 CFLAGS="$CFLAGS -Wno-attributes"
 CPPFLAGS="$CPPFLAGS -Wno-attributes"
 CXXFLAGS="$CXXFLAGS -Wno-attributes"
 
 export PKG_CONFIG_LIBDIR=/usr/local/lib64/pkgconfig:/usr/lib64/pkgconfig:/usr/share/pkgconfig
-. $topsrcdir/build/unix/mozconfig.gtk
 
 . "$topsrcdir/build/mozconfig.common.override"

--- a/browser/config/mozconfigs/linux64/nightly-asan
+++ b/browser/config/mozconfigs/linux64/nightly-asan
@@ -5,17 +5,16 @@ ac_add_options --enable-optimize="-O2 -g
 . $topsrcdir/build/mozconfig.stylo
 
 # ASan specific options on Linux
 ac_add_options --enable-valgrind
 
 . $topsrcdir/build/unix/mozconfig.asan
 
 export PKG_CONFIG_LIBDIR=/usr/local/lib64/pkgconfig:/usr/lib64/pkgconfig:/usr/share/pkgconfig
-. $topsrcdir/build/unix/mozconfig.gtk
 
 # Package js shell.
 export MOZ_PACKAGE_JSSHELL=1
 
 # Need this to prevent name conflicts with the normal nightly build packages
 export MOZ_PKG_SPECIAL=asan
 
 . "$topsrcdir/build/mozconfig.common.override"

--- a/browser/config/mozconfigs/linux64/nightly-asan-reporter
+++ b/browser/config/mozconfigs/linux64/nightly-asan-reporter
@@ -7,14 +7,13 @@ ac_add_options --enable-optimize="-O2 -g
 # ASan specific options on Linux
 ac_add_options --enable-valgrind
 
 . $topsrcdir/build/unix/mozconfig.asan
 
 ac_add_options --enable-address-sanitizer-reporter
 
 export PKG_CONFIG_LIBDIR=/usr/local/lib64/pkgconfig:/usr/lib64/pkgconfig:/usr/share/pkgconfig
-. $topsrcdir/build/unix/mozconfig.gtk
 
 # Need this to prevent name conflicts with the normal nightly build packages
 export MOZ_PKG_SPECIAL=asan-reporter
 
 . "$topsrcdir/build/mozconfig.common.override"

--- a/browser/config/mozconfigs/linux64/nightly-fuzzing-asan
+++ b/browser/config/mozconfigs/linux64/nightly-fuzzing-asan
@@ -8,17 +8,16 @@ ac_add_options --enable-optimize="-O2 -g
 ac_add_options --enable-valgrind
 
 . $topsrcdir/build/unix/mozconfig.fuzzing
 
 ac_add_options --enable-fuzzing
 unset MOZ_STDCXX_COMPAT
 
 export PKG_CONFIG_LIBDIR=/usr/local/lib64/pkgconfig:/usr/lib64/pkgconfig:/usr/share/pkgconfig
-. $topsrcdir/build/unix/mozconfig.gtk
 
 # Package js shell.
 export MOZ_PACKAGE_JSSHELL=1
 
 # Need this to prevent name conflicts with the normal nightly build packages
 export MOZ_PKG_SPECIAL=asan
 
 . "$topsrcdir/build/mozconfig.common.override"

--- a/browser/config/mozconfigs/linux64/opt-static-analysis-clang
+++ b/browser/config/mozconfigs/linux64/opt-static-analysis-clang
@@ -13,11 +13,10 @@ CC="$topsrcdir/clang/bin/clang"
 CXX="$topsrcdir/clang/bin/clang++"
 
 # Add the static checker
 ac_add_options --enable-clang-plugin
 
 . "$topsrcdir/build/unix/mozconfig.stdcxx"
 
 export PKG_CONFIG_LIBDIR=/usr/local/lib64/pkgconfig:/usr/lib64/pkgconfig:/usr/share/pkgconfig
-. $topsrcdir/build/unix/mozconfig.gtk
 
 . "$topsrcdir/build/mozconfig.common.override"

--- a/browser/config/mozconfigs/linux64/opt-tsan
+++ b/browser/config/mozconfigs/linux64/opt-tsan
@@ -1,9 +1,8 @@
 . $topsrcdir/build/unix/mozconfig.tsan
 
 export PKG_CONFIG_LIBDIR=/usr/local/lib64/pkgconfig:/usr/lib64/pkgconfig:/usr/share/pkgconfig
-. $topsrcdir/build/unix/mozconfig.gtk
 
 # Need this to prevent name conflicts with the normal nightly build packages
 export MOZ_PKG_SPECIAL=tsan
 
 . "$topsrcdir/build/mozconfig.common.override"

deleted file mode 100644
--- a/build/unix/mozconfig.gtk
+++ /dev/null
@@ -1,5 +0,0 @@
-# To do try builds with Gtk+2, uncomment the following line, and remove
-# everything after that.
-#ac_add_options --enable-default-toolkit=cairo-gtk2
-
-ac_add_options --enable-default-toolkit=cairo-gtk3

--- a/build/unix/mozconfig.linux
+++ b/build/unix/mozconfig.linux
@@ -23,10 +23,8 @@ else
   CC="/tools/gcc-4.7.3-0moz1/bin/gcc"
   CXX="/tools/gcc-4.7.3-0moz1/bin/g++"
 fi
 
 . "$topsrcdir/build/unix/mozconfig.stdcxx"
 
 # PKG_CONFIG_LIBDIR is appropriately overridden in mozconfig.linux32
 export PKG_CONFIG_LIBDIR=/usr/local/lib64/pkgconfig:/usr/lib64/pkgconfig:/usr/share/pkgconfig
-
-. "$topsrcdir/build/unix/mozconfig.gtk"