removed unused highlight.bg ini option

ext/standard/tests/strings/highlight_file.phpt

@@ -4,7 +4,6 @@ highlight_file() tests
 highlight.string=#DD0000
 highlight.comment=#FF9900
 highlight.keyword=#007700
-highlight.bg=#FFFFFF
 highlight.default=#0000BB
 highlight.html=#000000
 --FILE--

main/main.c

@@ -348,7 +348,6 @@ static PHP_INI_MH(OnUpdateDefaultMimetype)
  */
 PHP_INI_BEGIN()
 	PHP_INI_ENTRY_EX("define_syslog_variables",	"0",				PHP_INI_ALL,	NULL,			php_ini_boolean_displayer_cb)
-	PHP_INI_ENTRY_EX("highlight.bg",			HL_BG_COLOR,		PHP_INI_ALL,	NULL,			php_ini_color_displayer_cb)
 	PHP_INI_ENTRY_EX("highlight.comment",		HL_COMMENT_COLOR,	PHP_INI_ALL,	NULL,			php_ini_color_displayer_cb)
 	PHP_INI_ENTRY_EX("highlight.default",		HL_DEFAULT_COLOR,	PHP_INI_ALL,	NULL,			php_ini_color_displayer_cb)
 	PHP_INI_ENTRY_EX("highlight.html",			HL_HTML_COLOR,		PHP_INI_ALL,	NULL,			php_ini_color_displayer_cb)

php.ini-dist

@@ -167,7 +167,6 @@ disable_classes =
 ;highlight.string  = #DD0000
 ;highlight.comment = #FF9900
 ;highlight.keyword = #007700
-;highlight.bg      = #FFFFFF
 ;highlight.default = #0000BB
 ;highlight.html    = #000000
 

php.ini-recommended

@@ -200,7 +200,6 @@ disable_classes =
 ;highlight.string  = #DD0000
 ;highlight.comment = #FF9900
 ;highlight.keyword = #007700
-;highlight.bg      = #FFFFFF
 ;highlight.default = #0000BB
 ;highlight.html    = #000000
 

tests/strings/004.phpt

@@ -4,7 +4,6 @@ highlight_string() buffering
 highlight.string=#DD0000
 highlight.comment=#FF9900
 highlight.keyword=#007700
-highlight.bg=#FFFFFF
 highlight.default=#0000BB
 highlight.html=#000000
 --FILE--

tests/strings/bug26703.phpt

@@ -4,7 +4,6 @@ Bug #26703 (Certain characters inside strings incorrectly treated as keywords)
 highlight.string=#DD0000
 highlight.comment=#FF9900
 highlight.keyword=#007700
-highlight.bg=#FFFFFF
 highlight.default=#0000BB
 highlight.html=#000000
 --FILE--