[libcvd-members] CPP in autoconf

[Pablo Barrera]

Hello

I am having some problems with the autoconf file for my machine. I  
looks as it is not using the preprocessor.

The config.log says something like this:
configure:10640: checking ffmpeg/avcodec.h usability
configure:10657: g++ -c -g  -Wall -Wextra -ggdb -fPIC -mmmx -msse - 
msse -msse2 -msse3 -pthread  -I/Users/pablo/sw/include -I/opt/local/ 
include -I/sw/include -I/usr/X11R6/include conftest.cpp >&5
/sw/include/ffmpeg/avcodec.h:2265: warning: 'ImgReSampleContext' is  
deprecated (declared at /sw/include/ffmpeg/avcodec.h:2259)
/sw/include/ffmpeg/avcodec.h:2275: warning: 'ImgReSampleContext' is  
deprecated (declared at /sw/include/ffmpeg/avcodec.h:2259)
configure:10664: $? = 0
configure:10678: result: yes
configure:10682: checking ffmpeg/avcodec.h presence
configure:10697:   -I/Users/pablo/sw/include -I/opt/local/include -I/ 
sw/include -I/usr/X11R6/include conftest.cpp
./configure: line 10699: -I/Users/pablo/sw/include: No such file or  
directory
configure:10704: $? = 127

It is trying to execute -I/Users/pablo/sw/include. It seems the  
variable containing the preprocessor executable is empty. To solve  
this I have included AC_REQUIRE_CPP to configure.in, right after  
setting the language to C++:
...
#Switch testing language to C++
AC_LANG(C++)
AC_REQUIRE_CPP
...

According to the manual:
"Macro: AC_REQUIRE_CPP
Ensure that whichever preprocessor would currently be used for tests  
has been found. Calls AC_REQUIRE (see section Prerequisite Macros)  
with an argument of either AC_PROG_CPP or AC_PROG_CXXCPP, depending on  
which language is current."

I am using a mac:
Mac OS X - 10.5.4 - i386
autoconf --version
autoconf (GNU Autoconf) 2.62


Pablo