diff --git a/gnu/packages/cross-base.scm b/gnu/packages/cross-base.scm
index 6a09272..0992259 100644
--- a/gnu/packages/cross-base.scm
+++ b/gnu/packages/cross-base.scm
@@ -138,6 +138,10 @@ base compiler and using LIBC (which may be either a libc package or #f.)"
                                "--disable-libquadmath"
                                "--disable-decimal-float" ;would need libc
                                "--disable-libcilkrts"
+                               ,@(if (string-prefix? "powerpc64le-" target)
+                               ;; On POWER9 (little endian) glibc needs the 128 bit long double type.
+                               '("--with-long-double-128")
+                               '())
 
                                ;; When target is any OS other than 'none' these
                                ;; libraries will fail if there is no libc