问关于makefile的一个问题

在makefile里面有如下格式：
ifeq ($(GOAL),$(findstring $(GOAL),$(ES3883_TARGETS)))
TV_FLAGS= -DES3207V
endif

请问ifeq

endif

是什么意思？
---------------------------------------------------------------

If the two strings match exactly (except for leading or trailing whitespace), then the first set of lines is used; otherwise the second is used. The else clause is optional.

There are several different acceptable syntaxes for the ifeq and ifneq statements:

ifeq string1, string2
ifeq "string1", "string2"
ifeq 'string1', 'string2'
ifeq string1, string2

are all equivalent.

$(findstring

1<find>,<in>)   
2名称：查找字符串函数——findstring。   
3功能：在字串<in>中查找<find>字串。   
4返回：如果找到，那么返回<find>，否则返回空字符串。</find></find></in></in></find>