error when trying to ./build.sh in git repo

[Toni500github]

i'm getting this error when running ./build.sh

[~/git/the_silver_searcher]$ ./build.sh
configure.ac:10: installing './compile'
configure.ac:22: installing './config.guess'
configure.ac:22: installing './config.sub'
configure.ac:8: installing './install-sh'
configure.ac:8: installing './missing'
Makefile.am: installing './depcomp'
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /usr/bin/mkdir -p
checking for gawk... gawk
checking whether make sets $(MAKE)... yes
checking whether make supports nested variables... yes
checking for gcc... gcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables...
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking whether gcc understands -c and -o together... yes
checking whether make supports the include directive... yes (GNU style)
checking dependency style of gcc... gcc3
checking for grep that handles long lines and -e... /usr/bin/grep
checking whether make supports nested variables... (cached) yes
./configure: line 4008: syntax error near unexpected token PCRE,' ./configure: line 4008: PKG_CHECK_MODULES(PCRE, libpcre)'