diff --git a/portage/env/gcc-basic.conf b/portage/env/gcc-basic.conf
index be50da0..9ab37b3 100644
--- a/portage/env/gcc-basic.conf
+++ b/portage/env/gcc-basic.conf
@@ -6,6 +6,7 @@
 # Toolchain.
 AR="ar"
 CC="gcc"
+CPP="cpp"
 CXX="g++"
 NM="nm"
 RANLIB="ranlib"
diff --git a/portage/env/gcc-nolto-nopie.conf b/portage/env/gcc-nolto-nopie.conf
index b3abb11..e241d29 100644
--- a/portage/env/gcc-nolto-nopie.conf
+++ b/portage/env/gcc-nolto-nopie.conf
@@ -6,6 +6,7 @@
 # Toolchain.
 AR="ar"
 CC="gcc"
+CPP="cpp"
 CXX="g++"
 NM="nm"
 RANLIB="ranlib"
diff --git a/portage/env/gcc-nolto.conf b/portage/env/gcc-nolto.conf
index 00bb2b9..4dee312 100644
--- a/portage/env/gcc-nolto.conf
+++ b/portage/env/gcc-nolto.conf
@@ -6,6 +6,7 @@
 # Toolchain.
 AR="ar"
 CC="gcc"
+CPP="cpp"
 CXX="g++"
 NM="nm"
 RANLIB="ranlib"
diff --git a/portage/env/gcc-nopie.conf b/portage/env/gcc-nopie.conf
index b6f082e..bd4c091 100644
--- a/portage/env/gcc-nopie.conf
+++ b/portage/env/gcc-nopie.conf
@@ -6,6 +6,7 @@
 # Toolchain.
 AR="ar"
 CC="gcc"
+CPP="cpp"
 CXX="g++"
 NM="nm"
 RANLIB="ranlib"