HTTP: increase EXPECT_100_THRESHOLD to 1Mb

Mentioned: https://curl.haxx.se/mail/lib-2020-01/0050.html

Closes #4814

docs/libcurl/opts/CURLOPT_POSTFIELDS.3

@@ -54,8 +54,8 @@ the POST data from the read callback. If you want to send a zero-byte POST set
 
 Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header,
 and libcurl will add that header automatically if the POST is either known to
-be larger than 1024 bytes or if the expected size is unknown. You can disable
-this header with \fICURLOPT_HTTPHEADER(3)\fP as usual.
+be larger than 1MB or if the expected size is unknown. You can disable this
+header with \fICURLOPT_HTTPHEADER(3)\fP as usual.
 
 To make multipart/formdata posts (aka RFC2388-posts), check out the
 \fICURLOPT_HTTPPOST(3)\fP option combined with \fIcurl_formadd(3)\fP.

lib/http.h

@@ -116,7 +116,7 @@ CURLcode Curl_http_auth_act(struct connectdata *conn);
  *
  */
 #ifndef EXPECT_100_THRESHOLD
-#define EXPECT_100_THRESHOLD 1024
+#define EXPECT_100_THRESHOLD (1024*1024)
 #endif
 
 #endif /* CURL_DISABLE_HTTP */

tests/data/test1070

@@ -32,7 +32,7 @@ http
 HTTP POST with server closing connection before (all) data is received
  </name>
  <command>
- -d @log/input1070 http://%HOSTIP:%HTTPPORT/1070
+ -d @log/input1070 http://%HOSTIP:%HTTPPORT/1070 -H "Expect: 100-continue"
 </command>
 <file name="log/input1070">
 This creates the named file with this content before the test case is run,
@@ -55,9 +55,9 @@ OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
 POST /1070 HTTP/1.1
 Host: %HOSTIP:%HTTPPORT
 Accept: */*
+Expect: 100-continue
 Content-Length: 2313
 Content-Type: application/x-www-form-urlencoded
-Expect: 100-continue
 
 This creates 
 </protocol>

tests/data/test1133

@@ -48,7 +48,6 @@ User-Agent: curl/7.10.4 (i686-pc-linux-gnu) libcurl/7.10.4 OpenSSL/0.9.7a ipv6 z
 Host: %HOSTIP:%HTTPPORT
 Accept: */*
 Content-Length: 1264
-Expect: 100-continue
 Content-Type: multipart/form-data; boundary=----------------------------24e78000bd32
 
 ------------------------------24e78000bd32

tests/data/test304

@@ -49,7 +49,6 @@ User-Agent: curl/7.10.4 (i686-pc-linux-gnu) libcurl/7.10.4 OpenSSL/0.9.7a ipv6 z
 Host: %HOSTIP:%HTTPSPORT
 Accept: */*
 Content-Length: 1386
-Expect: 100-continue
 Content-Type: multipart/form-data; boundary=----------------------------c3b2ef7f0bb8
 
 ------------------------------c3b2ef7f0bb8

tests/data/test39

@@ -48,7 +48,6 @@ User-Agent: curl/7.10.4 (i686-pc-linux-gnu) libcurl/7.10.4 OpenSSL/0.9.7a ipv6 z
 Host: %HOSTIP:%HTTPPORT
 Accept: */*
 Content-Length: 1184
-Expect: 100-continue
 Content-Type: multipart/form-data; boundary=----------------------------24e78000bd32
 
 ------------------------------24e78000bd32

tests/data/test651

@@ -61,7 +61,6 @@ Host: %HOSTIP:%HTTPPORT
 Accept: */*
 Content-Length: 17139
 Content-Type: multipart/form-data; boundary=----------------------------
-Expect: 100-continue
 
 ------------------------------
 Content-Disposition: form-data; name="hello"