Add SHELL=/bin/sh definition, to override SGI make's default to $SHELL.
diff --git a/Misc/Makefile.pre.in b/Misc/Makefile.pre.in
index e9caa80..32e59d4 100644
--- a/Misc/Makefile.pre.in
+++ b/Misc/Makefile.pre.in
@@ -126,6 +126,9 @@
 
 # === Fixed definitions ===
 
+# Shell used by make (some versions default to the login shell, which is bad)
+SHELL=		/bin/sh
+
 # Expanded directories
 BINDIR=		$(exec_installdir)/bin
 LIBDIR=		$(exec_prefix)/lib