ecpg: avoid adding whitespace around '&' in connection URLs.

The preprocessor really should not have done this to begin with.
The space after '&' was masked by ECPGconnect's skipping spaces
before option keywords, and the space before by dint of libpq
being (mostly) insensitive to trailing space in option values.
We fixed the one known problem with that in 920d51979.  Hence
this patch is mostly cosmetic, and we'll just change it in HEAD.

Discussion: https://postgr.es/m/TY2PR01MB36286A7B97B9A15793335D18C1772@TY2PR01MB3628.jpnprd01.prod.outlook.com

src/interfaces/ecpg/ecpglib/connect.c

@@ -579,7 +579,10 @@ ECPGconnect(int lineno, int c, const char *name, const char *user, const char *p
 		 * The options string contains "keyword=value" pairs separated by
 		 * '&'s.  We must break this up into keywords and values to pass to
 		 * libpq (it's okay to scribble on the options string).  We ignore
-		 * spaces just before each keyword or value.
+		 * spaces just before each keyword or value.  (The preprocessor used
+		 * to add spaces around '&'s, making it necessary to ignore spaces
+		 * before keywords here.  While it no longer does that, we still must
+		 * skip spaces to support code compiled with older preprocessors.)
 		 */
 		for (str = options; *str;)
 		{

src/interfaces/ecpg/preproc/ecpg.trailer

@@ -348,7 +348,7 @@ connect_options: ColId opt_opt_value
 		if (strcmp($3, "&") != 0)
 			mmerror(PARSE_ERROR, ET_ERROR, "unrecognized token \"%s\"", $3);
 
-		$$ = cat_str(3, make2_str($1, $2), $3, $4);
+		$$ = make3_str(make2_str($1, $2), $3, $4);
 	}
 	;
 

src/interfaces/ecpg/test/expected/connect-test5.c

@@ -117,7 +117,7 @@ main(void)
 #line 56 "test5.pgc"
 
 
-	{ ECPGconnect(__LINE__, 0, "unix:postgresql://localhost/ecpg2_regression?connect_timeout=180 & client_encoding=sql_ascii" , "regress_ecpg_user1" , "connectpw" , "main", 0); }
+	{ ECPGconnect(__LINE__, 0, "unix:postgresql://localhost/ecpg2_regression?connect_timeout=180&client_encoding=sql_ascii" , "regress_ecpg_user1" , "connectpw" , "main", 0); }
 #line 58 "test5.pgc"
 
 	{ ECPGdisconnect(__LINE__, "main");}

src/interfaces/ecpg/test/expected/connect-test5.stderr

@@ -50,7 +50,7 @@
 [NO_PID]: sqlca: code: 0, state: 00000
 [NO_PID]: ecpg_finish: connection main closed
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ECPGconnect: opening database ecpg2_regression on <DEFAULT> port <DEFAULT> with options connect_timeout=180 & client_encoding=sql_ascii for user regress_ecpg_user1
+[NO_PID]: ECPGconnect: opening database ecpg2_regression on <DEFAULT> port <DEFAULT> with options connect_timeout=180&client_encoding=sql_ascii for user regress_ecpg_user1
 [NO_PID]: sqlca: code: 0, state: 00000
 [NO_PID]: ecpg_finish: connection main closed
 [NO_PID]: sqlca: code: 0, state: 00000