diff --git a/configure.ac b/configure.ac
index 5d1895f3..4a8c6f14 100644
--- a/configure.ac
+++ b/configure.ac
@@ -474,6 +474,7 @@ fi
 
 AC_SUBST(LIBCOAP_NAME_SUFFIX)
 AC_SUBST(LIBCOAP_DTLS_LIB_EXTENSION_NAME)
+AC_SUBST([DOLLAR_SIGN],[$])
 
 # configure options
 # __tests__
diff --git a/man/Makefile.am b/man/Makefile.am
index 24e95128..48eba65d 100644
--- a/man/Makefile.am
+++ b/man/Makefile.am
@@ -53,7 +53,7 @@ man7_MANS = $(MAN7)
 	$(A2X) --doctype manpage --format xhtml $<
 
 # Man pages built byt a2x based on the NAMES section of the .txt file
-A2X_EXTRA_PAGES := $(shell for fil in $(TXT3); do sed -ne '/^NAME/,/^SYNOPSIS/p;/^SYNOPSIS/q' $${fil} | \
+A2X_EXTRA_PAGES = @DOLLAR_SIGN@(shell for fil in $(TXT3) ; do sed -ne '/^NAME/,/^SYNOPSIS/p;/^SYNOPSIS/q' $${fil} | \
 	sed -ne '/coap_/{ s/ *, */\n/g; p }' | sed -ne 's/^\(coap_[a-zA-Z_]\+\).*$$/\1.3/p' ; done)
 
 # Extra man pages that need to be installed due to limit of 10