BUILD: Make deviceatlas require PCRE

Makefile deviceatlas throwing an error if the necessary pcre flag
is not passed avoiding surprising bunch of 'undefined reference'
for the user. Plus a tiny typo in OPENSSL area.

[wt: backport to 1.6]
diff --git a/Makefile b/Makefile
index 3af735e..d42d5fb 100644
--- a/Makefile
+++ b/Makefile
@@ -569,7 +569,7 @@
 endif
 
 ifneq ($(USE_OPENSSL),)
-# OpenSSL is packaged in various forms and with various dependences.
+# OpenSSL is packaged in various forms and with various dependencies.
 # In general -lssl is enough, but on some platforms, -lcrypto may be needed,
 # reason why it's added by default. Some even need -lz, then you'll need to
 # pass it in the "ADDLIB" variable if needed. If your SSL libraries are not
@@ -614,6 +614,9 @@
 endif
 
 ifneq ($(USE_DEVICEATLAS),)
+ifeq ($(USE_PCRE),)
+$(error the DeviceAtlas module needs the PCRE library in order to compile)
+endif
 # Use DEVICEATLAS_SRC and possibly DEVICEATLAS_INC and DEVICEATLAS_LIB to force path
 # to DeviceAtlas headers and libraries if needed.
 DEVICEATLAS_SRC =