Building native extensions.  This could take a while...                         
ERROR:  Error installing tmail:                                                 
        ERROR: Failed to build gem native extension.                            

/home/ruby19/bin/ruby extconf.rb install tmail
creating Makefile                             

make
gcc -I. -I/home/ruby19/include/ruby-1.9.1/x86_64-linux -I/home/ruby19/include/ruby-1.9.1/ruby/backward
-I/home/ruby19/include/ruby-1.9.1 -I.   -fPIC  -O2 -g -Wall -Wno-parentheses  -fPIC -D_FILE_OFFSET_BITS=64  -o tmailscanner.o
-c tmailscanner.c
tmailscanner.c:19:16: error: re.h: No such file or directory                    
tmailscanner.c: In function ‘mails_s_new’:                                      
tmailscanner.c:75: error: ‘struct RString’ has no member named ‘ptr’            
tmailscanner.c:77: error: ‘struct RString’ has no member named ‘len’            
tmailscanner.c: In function ‘skip_japanese_string’:                             
tmailscanner.c:188: warning: implicit declaration of function ‘ismbchar’        
tmailscanner.c:189: warning: implicit declaration of function ‘mbclen’
tmailscanner.c: In function ‘digit_p’:
tmailscanner.c:379: error: ‘struct RString’ has no member named ‘ptr’
tmailscanner.c:380: error: ‘struct RString’ has no member named ‘len’
tmailscanner.c:381: error: ‘struct RString’ has no member named ‘ptr’
tmailscanner.c:381: error: ‘struct RString’ has no member named ‘ptr’
tmailscanner.c: In function ‘atomsym’:
tmailscanner.c:399: error: ‘struct RString’ has no member named ‘ptr’
tmailscanner.c: In function ‘debug_print’:
tmailscanner.c:420: error: ‘struct RString’ has no member named ‘ptr’
tmailscanner.c:421: error: ‘struct RString’ has no member named ‘ptr’
make: *** [tmailscanner.o] Error 1