make test fails at #102 and #115
If you look at the file after the test

devel/libtool-base/work/
libtool-2.4.2/tests/testsuite.dir/115/tests/testsuite.dir/102/testsuite.log 

Following line may be the point of failure

lib2/.libs/libb.so: undefined reference to `a2(char)'

The related file, or origin of the test may be found at:

devel/libtool-base/work/libtool-2.4.2/tests/template.at

   144  AT_DATA(src/lib/a.hh,
   145  [[template <class T>
   146  unsigned int a(const T&);
   147  
   148  template <class T>
   149  unsigned int a(const T& t)
   150  {
   151    return sizeof t;
   152  }
   153  
   154  extern int a2(char t);
   155  
   156  inline int a3(const double* t)
   157  {
   158    return a(t);
   159  }
   160  ]])
   161  
   162  AT_DATA(src/lib/a.cpp,
   163  [[#include "a.hh"
   164  
   165  int a2(char t)
   166  {
   167    return a(t);
   168  }
   169  ]])
   170  
   171  AT_DATA(src/lib2/b.hh,
   172  [[#include "a.hh"
   173  
   174  template <class T>
   175  unsigned int b(T& t)
   176  {
   177    return a(t);
   178  }
   179  extern int b2(char* t);
   180  struct bs { int bi; };
   181  extern int b3(bs t);
   182  ]])
   183  
   184  AT_DATA(src/lib2/b.cpp,
   185  [[#include "b.hh"
   186  
   187  int b2(char* t)
   188  {
   189    return a2(t[0]);
   190  }

#102 and #115 appears in testsuite.log as following context

C++ template tests.

101: simple template test                   ok
102: template test with subdirs             FAILED (template.at:230)

Detecting identical deplibs.

109: build tree relpaths                    UNEXPECTED PASS

Libtool stress test.

114: Link option thorough search test       ok
115: Run tests with low max_cmd_len         FAILED (cmdline_wrap.at:43)
116: override pic_flag at configure time    skipped (pic_flag.at:47)