[gentoo-dev] [PATCH] cmake.eclass: Set CMAKE_SYSROOT when building with SYSROOT=

[James Le Cuirot <chewi@gentoo.org>]

From: Raul E Rangel <rrangel@chromium.org>

When performing a SYSROOT= build, the --sysroot parameter was not
getting passed to the compiler if the CBUILD and CHOST matched. This
results in the build attempting to use BROOT libraries and headers
instead of the ones from the SYSROOT.

This change will allow `llvm` to be built into a new SYSROOT.

    ROOT=/build/amd64-host emerge sys-devel/llvm

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Closes: https://github.com/gentoo/gentoo/pull/30658
Signed-off-by: James Le Cuirot <chewi@gentoo.org>
---
 eclass/cmake.eclass | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/eclass/cmake.eclass b/eclass/cmake.eclass
index 24787f1c2a49..1cdbc123a243 100644
--- a/eclass/cmake.eclass
+++ b/eclass/cmake.eclass
@@ -484,17 +484,17 @@ cmake_src_configure() {
 		cat >> "${toolchain_file}" <<- _EOF_ || die
 			set(CMAKE_SYSTEM_NAME "${sysname}")
 		_EOF_
+	fi
 
-		if [ "${SYSROOT:-/}" != "/" ] ; then
-			# When cross-compiling with a sysroot (e.g. with crossdev's emerge wrappers)
-			# we need to tell cmake to use libs/headers from the sysroot but programs from / only.
-			cat >> "${toolchain_file}" <<- _EOF_ || die
-				set(CMAKE_SYSROOT "${ESYSROOT}")
-				set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
-				set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
-				set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
-			_EOF_
-		fi
+	if [[ ${SYSROOT:-/} != / ]] ; then
+		# When building with a sysroot (e.g. with crossdev's emerge wrappers)
+		# we need to tell cmake to use libs/headers from the sysroot but programs from / only.
+		cat >> "${toolchain_file}" <<- _EOF_ || die
+			set(CMAKE_SYSROOT "${ESYSROOT}")
+			set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+			set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+			set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+		_EOF_
 	fi
 
 	if use prefix-guest; then
-- 
2.40.1