have_library: checking for gdbm_open() in -lgdbm... -------------------- no

"gcc -o conftest -I../../.ext/include/x86_64-linux -I../.././include -I../.././ext/gdbm     -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wimplicit-function-declaration -Wdeprecated-declarations -Wno-packed-bitfield-compat  -fPIC conftest.c  -L. -L../.. -L. -fstack-protector -rdynamic -Wl,-export-dynamic     -Wl,-R/usr/local/rvm/rubies/ruby-2.2.10/lib -L/usr/local/rvm/rubies/ruby-2.2.10/lib -lruby-static -lgdbm  -lpthread -ldl -lcrypt -lm   -lc"
conftest.c: In function ‘t’:
conftest.c:13:57: error: ‘gdbm_open’ undeclared (first use in this function); did you mean ‘fmemopen’?
 int t(void) { void ((*volatile p)()); p = (void ((*)()))gdbm_open; return 0; }
                                                         ^~~~~~~~~
                                                         fmemopen
conftest.c:13:57: note: each undeclared identifier is reported only once for each function it appears in
conftest.c:13:32: warning: variable ‘p’ set but not used [-Wunused-but-set-variable]
 int t(void) { void ((*volatile p)()); p = (void ((*)()))gdbm_open; return 0; }
                                ^
checked program was:
/* begin */
 1: #include "ruby.h"
 2: 
 3: /*top*/
 4: extern int t(void);
 5: int main(int argc, char **argv)
 6: {
 7:   if (argc > 1000000) {
 8:     printf("%p", &t);
 9:   }
10: 
11:   return 0;
12: }
13: int t(void) { void ((*volatile p)()); p = (void ((*)()))gdbm_open; return 0; }
/* end */

"gcc -o conftest -I../../.ext/include/x86_64-linux -I../.././include -I../.././ext/gdbm     -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wimplicit-function-declaration -Wdeprecated-declarations -Wno-packed-bitfield-compat  -fPIC conftest.c  -L. -L../.. -L. -fstack-protector -rdynamic -Wl,-export-dynamic     -Wl,-R/usr/local/rvm/rubies/ruby-2.2.10/lib -L/usr/local/rvm/rubies/ruby-2.2.10/lib -lruby-static -lgdbm  -lpthread -ldl -lcrypt -lm   -lc"
conftest.c: In function ‘t’:
conftest.c:13:15: warning: implicit declaration of function ‘gdbm_open’; did you mean ‘fmemopen’? [-Wimplicit-function-declaration]
 int t(void) { gdbm_open(); return 0; }
               ^~~~~~~~~
               fmemopen
/usr/bin/ld: cannot find -lgdbm
collect2: error: ld returned 1 exit status
checked program was:
/* begin */
 1: #include "ruby.h"
 2: 
 3: /*top*/
 4: extern int t(void);
 5: int main(int argc, char **argv)
 6: {
 7:   if (argc > 1000000) {
 8:     printf("%p", &t);
 9:   }
10: 
11:   return 0;
12: }
13: int t(void) { gdbm_open(); return 0; }
/* end */

--------------------

Failed to configure gdbm. It will not be installed.