diff --git a/libisl/.SRCINFO b/libisl/.SRCINFO
index b5e022bd47..f876e697ef 100644
--- a/libisl/.SRCINFO
+++ b/libisl/.SRCINFO
@@ -1,9 +1,13 @@
 pkgbase = libisl
 	pkgdesc = Library for manipulating sets and relations of integer points bounded by linear constraints
 	pkgver = 0.27
-	pkgrel = 1
+	pkgrel = 1.1
 	url = https://libisl.sourceforge.io
 	arch = x86_64
+	arch = powerpc64le
+	arch = powerpc64
+	arch = powerpc
+	arch = riscv64
 	license = MIT
 	depends = gmp
 	provides = isl
@@ -11,6 +15,8 @@ pkgbase = libisl
 	replaces = isl
 	options = staticlibs
 	source = https://libisl.sourceforge.io/isl-0.27.tar.xz
+	source = isl-0.24-respect-flags.patch
 	b2sums = 88a68de0b7952eb0038d10aa450b0ab25da4f4aa49fcdf70700ec4131d2686a2a2e9a64e5cb8ac0a53ef5d7cff034e60c449b201ba88a24001ad33f0dd17c732
+	b2sums = 34d028a22ad608fbddf7a3909000351f7cf9b7e75cf3b0f687fafc35554163a123467053433c96c32764b155c02f01a336e92e67e25726bfd3e109ba18de42b7
 
 pkgname = libisl
diff --git a/libisl/PKGBUILD b/libisl/PKGBUILD
index 83200d7cd0..90d7307a66 100644
--- a/libisl/PKGBUILD
+++ b/libisl/PKGBUILD
@@ -7,7 +7,7 @@
 
 pkgname=libisl
 pkgver=0.27
-pkgrel=1
+pkgrel=1.1
 pkgdesc='Library for manipulating sets and relations of integer points bounded by linear constraints'
 arch=(x86_64 powerpc64le powerpc64 powerpc riscv64)
 url='https://libisl.sourceforge.io'
@@ -21,8 +21,15 @@ b2sums=('88a68de0b7952eb0038d10aa450b0ab25da4f4aa49fcdf70700ec4131d2686a2a2e9a64
 
 build() {
   cd "${srcdir}"/${pkgname#lib}-${pkgver}
-  ./configure --prefix=/usr
-  make
+
+  case "${CARCH}" in
+    powerpc)     _configure_flags=(--with-gcc-arch="750") ;;
+    powerpc64)   _configure_flags=(--with-gcc-arch="powerpc64") ;;
+    powerpc64le) _configure_flags=(--with-gcc-arch="power8") ;;
+  esac
+
+  ./configure --prefix=/usr ${_configure_flags[@]}
+  make VERBOSE=1
 }
 
 check() {