1 files changed, 5 insertions, 0 deletions
diff --git a/ghc.mk b/ghc.mk
index 02e3b79a2d..91cc5588c4 100644
--- a/ghc.mk
+++ b/ghc.mk
@@ -185,6 +185,11 @@ $(error BUILD_SPHINX_PDF=YES, but `xelatex` was not found. \
   Install `xelatex`, then rerun `./configure`. \
   See https://gitlab.haskell.org/ghc/ghc/wikis/building/preparation)
 endif
+ifeq "$(MAKEINDEX)" ""
+$(error BUILD_SPHINX_PDF=YES, but `makeindex` was not found. \
+  Install `xelatex`, then rerun `./configure`. \
+  See https://gitlab.haskell.org/ghc/ghc/wikis/building/preparation)
+endif
 endif
 
 ifeq "$(HSCOLOUR_SRCS)" "YES"