Re: How to interpret commands between colon and first tab ?

[Paul Smith]

On Mon, 2015-11-23 at 17:57 +0100, Ewan Delanoy wrote:
>      Hello all, I'm rather new to make (only used it without reading the
>    manual so far).
>      The "all" target in a makefile for gcc5-2.0 looks like below. Notice
>    that this code snippet contains
>    no tab at all after the colon (the first tab is much further in the
>    code). I could not find in the
>    GNU make manual a mention of how make treats those particular regions
>    in the makefile.

>    all:

The above introduces a rule "all:" which has no prerequisites and no
recipe (because the next non-whitespace, non-comment line is not
indented by a TAB).

>    #### host and target specific makefile fragments come in here.
>    # The -mdynamic-no-pic ensures that the compiler executable is built
>    without
>    # position-independent-code -- the usual default on Darwin. This fix
>    speeds
>    # compiles by 3-5%.  Don't add it if the compiler doesn't also support
>    # -mno-dynamic-no-pic to undo it.

These rest are just variable assignments, using the ":=" simple variable
assignment syntax.

>    DARWIN_MDYNAMIC_NO_PIC := \
>    `case ${host} in i?86-*-darwin* | powerpc-*-darwin*) \
>       $(CC) -S -xc /dev/null -o /dev/null -mno-dynamic-no-pic 2>/dev/null
>    \
>       && echo -mdynamic-no-pic ;; esac`
>    DARWIN_GCC_MDYNAMIC_NO_PIC := \
>    `case ${host} in i?86-*-darwin* | powerpc-*-darwin*) \
>       $(CC) -S -xc /dev/null -o /dev/null -mno-dynamic-no-pic 2>/dev/null
>    \
>       || echo -mdynamic-no-pic ;; esac`