compilation failed for package 'techchart'

[SNAnalyst]

When I try to install techchart, I get the error below.
I am on Win64, I have Rtools installed. Can you please help?

Downloading GitHub repo prodipta/techchart@HEAD
── R CMD build ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
✔ checking for file 'C:\Users\snanalyst\AppData\Local\Temp\RtmpWO2gTn\remotes6b3838af2e9a\prodipta-techchart-93f9106/DESCRIPTION' (389ms)
─ preparing 'techchart': (733ms)
✔ checking DESCRIPTION meta-information ...
─ cleaning src
─ checking for LF line-endings in source and make files and shell scripts
─ checking for empty or unneeded directories
─ building 'techchart_0.1.0.tar.gz'

Installing package into ‘C:/R/4.5/library’
(as ‘lib’ is unspecified)
Using model = "gpt-4o".

• installing source package 'techchart' ...
  ** this is package 'techchart' version '0.1.0'
  ** using staged installation
  ** libs
  using C++ compiler: 'G__1.EXE (GCC) 14.2.0'
  g++ -std=gnu++17 -I"C:/R/R-451.0/include" -DNDEBUG -I'C:/R/4.5/library/Rcpp/include' -I"C:/rtools45/x86_64-w64-mingw32.static.posix/include" -O2 -Wall -mfpmath=sse -msse2 -mstackrealign -c RcppExports.cpp -o RcppExports.o
  g++ -std=gnu++17 -I"C:/R/R-451.0/include" -DNDEBUG -I'C:/R/4.5/library/Rcpp/include' -I"C:/rtools45/x86_64-w64-mingw32.static.posix/include" -O2 -Wall -mfpmath=sse -msse2 -mstackrealign -c cpttrend.cpp -o cpttrend.o
  cpttrend.cpp: In function 'double ols_llk(Rcpp::NumericVector, Rcpp::NumericVector, long int)':
  cpttrend.cpp:142:27: error: 'PI' was not declared in this scope
  142 | ret = double(n)/2log(2PI) + double(n)/2*log(variance) + double(n)/2;
  | ^
  make: *** [C:/R/R-45~1.0/etc/x64/Makeconf:296: cpttrend.o] Error 1
  ERROR: compilation failed for package 'techchart'
• removing 'C:/R/4.5/library/techchart'
  Warning message:
  In i.p(...) :
  installation of package ‘C:/Users/snanalyst/AppData/Local/Temp/RtmpWO2gTn/file6b385d147be6/techchart_0.1.0.tar.gz’ had non-zero exit status