2 files changed, 22 insertions, 1 deletions
diff --git a/dev-cpp/eigen/eigen-3.4.1.ebuild b/dev-cpp/eigen/eigen-3.4.1-r1.ebuild
index 65f1b42f809f..6613dcead10b 100644
--- a/dev-cpp/eigen/eigen-3.4.1.ebuild
+++ b/dev-cpp/eigen/eigen-3.4.1-r1.ebuild
@@ -30,7 +30,7 @@ else
 		https://gitlab.com/libeigen/eigen/-/commit/0295f81a835ef69e2bacd9e75ab5782eca398720.patch -> ${P}_p1.patch
 		https://gitlab.com/libeigen/eigen/-/commit/28ded8800c26864e537852658428ab44c8399e87.patch -> ${P}_p2.patch
 	"
-	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~loong ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~arm64-macos ~x64-macos"
+	KEYWORDS="~alpha ~amd64 arm arm64 ~hppa ~loong ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~arm64-macos ~x64-macos"
 fi
 
 SRC_URI+="
@@ -231,6 +231,8 @@ PATCHES=(
 
 	"${DISTDIR}/${P}_p1.patch"
 	"${DISTDIR}/${P}_p2.patch"
+
+	"${FILESDIR}/${P}-fix-Werror-undef.patch" # bug 976285
 )
 
 # TODO should be in cuda.eclass
diff --git a/dev-cpp/eigen/files/eigen-3.4.1-fix-Werror-undef.patch b/dev-cpp/eigen/files/eigen-3.4.1-fix-Werror-undef.patch
new file mode 100644
index 000000000000..9772616e9c16
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-3.4.1-fix-Werror-undef.patch
@@ -0,0 +1,19 @@
+Fixes likely mistake in conflict resolution of upstream backport
+of a73970a8640330c4908d68ef9257fd31a4fdae9.
+
+EIGEN_COMP_CLANG_STRICT does not exist in 3.4 branch and was not
+touched in the original commit.
+
+Gentoo-bug: https://bugs.gentoo.org/976285
+
+--- a/Eigen/src/Core/util/ConfigureVectorization.h
++++ b/Eigen/src/Core/util/ConfigureVectorization.h
+@@ -445,7 +445,7 @@
+ #define EIGEN_VECTORIZE_FMA
+ #endif
+ 
+-#if defined(__F16C__) && !defined(EIGEN_GPUCC) && (!EIGEN_COMP_CLANG_STRICT || EIGEN_COMP_CLANG>=380)
++#if defined(__F16C__) && (!defined(EIGEN_GPUCC) && (!defined(EIGEN_COMP_CLANG) || EIGEN_COMP_CLANG>=380))
+   // We can use the optimized fp16 to float and float to fp16 conversion routines
+   #define EIGEN_HAS_FP16_C
+