Only in b/cfitsio: autom4te.cache
diff --recursive -u -p a/cfitsio/configure b/cfitsio/configure
--- a/cfitsio/configure	2018-05-09 15:16:00.000000000 -0400
+++ b/cfitsio/configure	2018-08-06 15:42:35.000000000 -0400
@@ -710,6 +710,7 @@ enable_reentrant
 enable_sse2
 enable_ssse3
 enable_hera
+enable_curl
 with_bzip2
 with_gsiftp
 with_gsiftp_flavour
@@ -1341,6 +1342,7 @@ Optional Features:
   --enable-ssse3          Enable use of instructions in the SSSE3 extended
                           instruction set
   --enable-hera           Build for HERA (ASD use only)
+  --disable-curl          Disable use of cURL library (HTTPS)
 
 Optional Packages:
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
@@ -2264,6 +2266,13 @@ if test "x$BUILD_HERA" = xyes; then
 
 fi
 
+# Check whether --enable-curl was given.
+if test "${enable_curl+set}" = set; then :
+  enableval=$enable_curl;  if test $enableval = yes; then CURL_DISABLED=yes; fi
+
+fi
+
+
 # Optional support for bzip2 compression:
 ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
@@ -4780,17 +4789,18 @@ if test "x$CFITSIO_SHLIB" = x; then CFIT
 
 # Curl library (will be pulled in to the shared CFITSIO library):
 # ---------------------------------------------------------------
-CURL_LIB=""
-CURL_INC=""
-# Use curl-config to get compiler & linker flags, if available.
-# On Macs, prefer XCode curl-config, and reject MacPorts version
-# until further notice to prevent build errors:
-if test "x$EXT" = xdarwin -a -x /usr/bin/curl-config; then
-  CURLCONFIG="/usr/bin/curl-config"
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: checking for curl-config... choosing /usr/bin/curl-config on Mac" >&5
+if test "x$CURL_DISABLED" != x; then
+  CURL_LIB=""
+  CURL_INC=""
+  # Use curl-config to get compiler & linker flags, if available.
+  # On Macs, prefer XCode curl-config, and reject MacPorts version
+  # until further notice to prevent build errors:
+  if test "x$EXT" = xdarwin -a -x /usr/bin/curl-config; then
+    CURLCONFIG="/usr/bin/curl-config"
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: checking for curl-config... choosing /usr/bin/curl-config on Mac" >&5
 $as_echo "checking for curl-config... choosing /usr/bin/curl-config on Mac" >&6; }
-else
-  # Extract the first word of "curl-config", so it can be a program name with args.
+  else
+    # Extract the first word of "curl-config", so it can be a program name with args.
 set dummy curl-config; ac_word=$2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
 $as_echo_n "checking for $ac_word... " >&6; }
@@ -4844,30 +4854,34 @@ $as_echo "no" >&6; }
 fi
 
 
-fi
-if test "x$CURLCONFIG" != x; then
-  CURL_LIB=`$CURLCONFIG --libs`
-  CURL_INC=`$CURLCONFIG --cflags`
-  # Also reject anaconda curl on Macs until further notice:
-  if test "x$EXT" = xdarwin -a `echo $CURL_LIB $CURL_INC | grep -ci anaconda` -gt 0; then
-    { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: Rejecting Anaconda curl. Disabling HTTPS support." >&5
+  fi
+  if test "x$CURLCONFIG" != x; then
+    CURL_LIB=`$CURLCONFIG --libs`
+    CURL_INC=`$CURLCONFIG --cflags`
+    # Also reject anaconda curl on Macs until further notice:
+    if test "x$EXT" = xdarwin -a `echo $CURL_LIB $CURL_INC | grep -ci anaconda` -gt 0; then
+      { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: Rejecting Anaconda curl. Disabling HTTPS support." >&5
 $as_echo "$as_me: WARNING: Rejecting Anaconda curl. Disabling HTTPS support." >&2;}
-  else
-    LIBS="$CURL_LIB $LIBS"
-    if test "x$CURL_INC" != x; then
-      CFLAGS="$CURL_INC $CFLAGS"
-    fi
-    $as_echo "#define CFITSIO_HAVE_CURL 1" >>confdefs.h
+    else
+      LIBS="$CURL_LIB $LIBS"
+      if test "x$CURL_INC" != x; then
+        CFLAGS="$CURL_INC $CFLAGS"
+      fi
+      $as_echo "#define CFITSIO_HAVE_CURL 1" >>confdefs.h
 
+    fi
+  # No curl-config:
+  else
+    { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: curl-config not found. Disabling HTTPS support." >&5
+$as_echo "$as_me: WARNING: curl-config not found. Disabling HTTPS support." >&2;}
+  # Incomplete stubs for possible future use:
+  #  AC_CHECK_LIB([curl],[main],[],
+  #       [AC_MSG_WARN(Not building curl support for CFITSIO)])
+  #  AC_CHECK_HEADER(curl.h,[])
   fi
-# No curl-config:
 else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: curl-config not found. Disabling HTTPS support." >&5
-$as_echo "$as_me: WARNING: curl-config not found. Disabling HTTPS support." >&2;}
-# Incomplete stubs for possible future use:
-#  AC_CHECK_LIB([curl],[main],[],
-#       [AC_MSG_WARN(Not building curl support for CFITSIO)])
-#  AC_CHECK_HEADER(curl.h,[])
+  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: curl disabled. Disabling HTTPS support." >&5
+$as_echo "$as_me: WARNING: curl disabled. Disabling HTTPS support." >&2;}
 fi
 
 # GSIFTP flags:
diff --recursive -u -p a/cfitsio/configure.in b/cfitsio/configure.in
--- a/cfitsio/configure.in	2018-05-09 15:16:00.000000000 -0400
+++ b/cfitsio/configure.in	2018-08-06 15:42:27.000000000 -0400
@@ -53,6 +53,12 @@ if test "x$BUILD_HERA" = xyes; then
   AC_DEFINE(BUILD_HERA)
 fi
 
+AC_ARG_ENABLE(
+  curl,
+  [AS_HELP_STRING([--disable-curl],[Disable use of cURL library (HTTPS)])],
+  [ if test $enableval = yes; then CURL_DISABLED=yes; fi ]
+)
+
 # Optional support for bzip2 compression:
 AC_ARG_WITH(
   bzip2,
@@ -441,37 +447,41 @@ if test "x$CFITSIO_SHLIB" = x; then CFIT
 
 # Curl library (will be pulled in to the shared CFITSIO library):
 # ---------------------------------------------------------------
-CURL_LIB=""
-CURL_INC=""
-# Use curl-config to get compiler & linker flags, if available.
-# On Macs, prefer XCode curl-config, and reject MacPorts version
-# until further notice to prevent build errors:
-if test "x$EXT" = xdarwin -a -x /usr/bin/curl-config; then
-  CURLCONFIG="/usr/bin/curl-config"
-  AC_MSG_RESULT(checking for curl-config... choosing /usr/bin/curl-config on Mac)
-else
-  AC_CHECK_PROG([CURLCONFIG], [curl-config], [curl-config], [], [], [/opt/local/bin/curl-config])
-fi
-if test "x$CURLCONFIG" != x; then
-  CURL_LIB=`$CURLCONFIG --libs`
-  CURL_INC=`$CURLCONFIG --cflags`
-  # Also reject anaconda curl on Macs until further notice:
-  if test "x$EXT" = xdarwin -a `echo $CURL_LIB $CURL_INC | grep -ci anaconda` -gt 0; then
-    AC_MSG_WARN(Rejecting Anaconda curl. Disabling HTTPS support.)
+if test "x$CURL_DISABLED" != x; then
+  CURL_LIB=""
+  CURL_INC=""
+  # Use curl-config to get compiler & linker flags, if available.
+  # On Macs, prefer XCode curl-config, and reject MacPorts version
+  # until further notice to prevent build errors:
+  if test "x$EXT" = xdarwin -a -x /usr/bin/curl-config; then
+    CURLCONFIG="/usr/bin/curl-config"
+    AC_MSG_RESULT(checking for curl-config... choosing /usr/bin/curl-config on Mac)
   else
-    LIBS="$CURL_LIB $LIBS"
-    if test "x$CURL_INC" != x; then
-      CFLAGS="$CURL_INC $CFLAGS"
+    AC_CHECK_PROG([CURLCONFIG], [curl-config], [curl-config], [], [], [/opt/local/bin/curl-config])
+  fi
+  if test "x$CURLCONFIG" != x; then
+    CURL_LIB=`$CURLCONFIG --libs`
+    CURL_INC=`$CURLCONFIG --cflags`
+    # Also reject anaconda curl on Macs until further notice:
+    if test "x$EXT" = xdarwin -a `echo $CURL_LIB $CURL_INC | grep -ci anaconda` -gt 0; then
+      AC_MSG_WARN(Rejecting Anaconda curl. Disabling HTTPS support.)
+    else
+      LIBS="$CURL_LIB $LIBS"
+      if test "x$CURL_INC" != x; then
+        CFLAGS="$CURL_INC $CFLAGS"
+      fi
+      AC_DEFINE(CFITSIO_HAVE_CURL)
     fi
-    AC_DEFINE(CFITSIO_HAVE_CURL)
+  # No curl-config:
+  else
+    AC_MSG_WARN(curl-config not found. Disabling HTTPS support.)
+  # Incomplete stubs for possible future use:
+  #  AC_CHECK_LIB([curl],[main],[],
+  #       [AC_MSG_WARN(Not building curl support for CFITSIO)])
+  #  AC_CHECK_HEADER(curl.h,[])
   fi
-# No curl-config:
 else
-  AC_MSG_WARN(curl-config not found. Disabling HTTPS support.)
-# Incomplete stubs for possible future use:
-#  AC_CHECK_LIB([curl],[main],[],
-#       [AC_MSG_WARN(Not building curl support for CFITSIO)])
-#  AC_CHECK_HEADER(curl.h,[])
+  AC_MSG_WARN(curl disabled. Disabling HTTPS support.)
 fi
 
 # GSIFTP flags: